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Co-transcriptional assembly is an integral feature of the formation of RNA-protein complexes that mediate translation. For ribosome synthesis, prior studies have indicated that the strict order of transcription of rRNA domains may not be obligatory during bacterial ribosome biogenesis, since a series of circularly permuted rRNAs are viable. In this work, we report the structural insights into assembly of the bacterial ribosome large subunit (LSU) based on cryo-EM density maps of intermediates that accumulate during in vitro ribosome synthesis using a set of circularly permuted (CiPer) rRNAs. The observed ensemble of 23 resolved ribosome large subunit intermediates reveals conserved assembly routes with an underlying hierarchy among cooperative assembly blocks. There are intricate interdependencies for the formation of key structural rRNA helices revealed from the circular permutation of rRNA. While the order of domain synthesis is not obligatory, the order of domain association does appear to proceed with a particular order, likely due to the strong evolutionary pressure on efficient ribosome synthesis. This work reinforces the robustness of the known assembly hierarchy of the bacterial large ribosomal subunit and offers a coherent view of how efficient assembly of CiPer rRNAs can be understood in that context., (© The Author(s) 2024. Published by Oxford University Press on behalf of Nucleic Acids Research.)

Structural biology efforts using cryogenic electron microscopy are frequently stifled by specimens adopting "preferred orientations" on grids, leading to anisotropic map resolution and impeding structure determination. Tilting the specimen stage during data collection is a generalizable solution but has historically led to substantial resolution attenuation. Here, we develop updated data collection and image processing workflows and demonstrate, using multiple specimens, that resolution attenuation is negligible or significantly reduced across tilt angles. Reconstructions with and without the stage tilted as high as 60° are virtually indistinguishable. These strategies allowed the reconstruction to 3 Å resolution of a bacterial RNA polymerase with preferred orientation, containing an unnatural nucleotide for studying novel base pair recognition. Furthermore, we present a quantitative framework that allows cryo-EM practitioners to define an optimal tilt angle during data acquisition. These results reinforce the utility of employing stage tilt for data collection and provide quantitative metrics to obtain isotropic maps., (© 2024. The Author(s).)

Introduction: Instrumentation using the intraoperative O-arm navigation technique appears safer than its predecessor techniques. However, only a handful of surgeons often used navigation during spinal surgeries. Too many operative glitches and unreliable navigation accuracy were the important reasons cited even by experienced surgeons for not using spinal navigation. We have studied the accuracy of pedicle screw placement during the learning curve and beyond it. We have also discussed in detail the intricacies of the technique and solutions to the difficulties encountered using spinal navigation., Materials and Methods: A total of 2000 thoracolumbar pedicle screws have been placed in the 324 spine surgeries meeting the inclusion and exclusion criteria included in this retrospective study. We have divided 2000 pedicle screw placements into consecutive groups of 200 each. We have compared these groups for the accuracy of screw placement with the surgeon's experience., Results: The accuracy of pedicle screw placement using the "in-versus-out" grading system in group 1 was 85.5% which significantly increased in group 2 to 93.5% (p-value: 0.0099), and thereafter, there was a nonsignificant increase in subsequent groups with the graph achieving the shape of a plateau., Conclusion: Surgeons should learn the correct principles of the technique of O-arm navigation to prevent the loss of accuracy and place pedicle screws with high accuracy. There is a learning curve of around 30-35 surgeries or 200 pedicle screw placements to acclimatize with the technique of O-arm navigation and learn its principles., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Free-hand and fluoroscopic-guided pedicle screw placement has been associated with higher rates of pedicle breaches (frequency range 15-40% especially in deformed pedicles). Neurological complications are more "critical" (i.e., frequent and significant) with medial and inferior pedicle-wall breaches due to the proximity of the neural elements. Here, we analyzed the effectiveness of O-arm navigation in minimizing "critical" pedicle wall breaches and their complications in 21 complex spinal deformity cases., Methods: Twenty-one complex spinal deformity cases were prospectively managed with O-arm-navigated posterior-instrumented fusions. Preoperative assessment included; evaluation of the type of scoliosis, the magnitude of the deformity, and the anatomy of the pedicles - (i.e., classified using Watanabe et al .). The O-arm was used to confirm and grade both the intraoperative and postoperative location of screws. Other variables analyzed included; duration of surgery, estimated blood loss, complications, and radiation exposure., Results: In 21 patients, 259 (63.45%) of 384 pedicles were instrumented; we observed 22 of 259 pedicle screw breaches. Significant (>2 mm) breaches were observed in two medial and one inferior wall cases that required revision; the overall biomechanically significant screw breach rate was (3/259) 1.2% with an accuracy rate of 98.8%. Pedicle screw placement resulted in another 14 nonsignificant (<2 mm) breaches; ten were medial and four involved the inferior wall. As anterior, lateral, and "in-out-in" trajectory pedicle screws beaches were nonsignificant, they were not included in our analysis., Conclusion: O-arm navigation decreased the incidence of medial and inferior (i.e., >2 mm "critical") pedicle screw breaches applied in 21 patients with deformed pedicles due to scoliosis. Further, the O-arm minimized the operating time, decreased the estimated blood loss, and reduced the incidence of complications., Competing Interests: There are no conflicts of interest., (Copyright: © 2023 Surgical Neurology International.)

Cardiomyopathy is a major cause of heart failure caused by abnormalities of the heart muscles that make it harder for it to fill or eject blood. With technological advances, it is important for patients and families to understand that there are potential monogenic etiologies of cardiomyopathy. A multidisciplinary approach to clinical genetic screening for cardiomyopathies involving genetic counseling and clinical genetic testing is beneficial for patients and families. With early identification of inherited cardiomyopathy, patients can initiate guideline-directed medical therapies earlier, resulting in a greater likelihood of improving prognoses and health outcomes. Identifying impactful genetic variants will also allow for cascade testing to determine at-risk family members through clinical (phenotype) screening and risk stratification. Addressing genetic variants of uncertain significance and causative variants that may change in pathogenicity is also important to consider. This review will dive into the clinical genetic testing approaches for the various cardiomyopathies, the significance of early detection and treatment, the value of family screening, the personalized treatment process associated with genetic evaluation, and current strategies for clinical genetic testing outreach.

Clinical trials are conducted to evaluate the usefulness of a drug, medical treatment, surgical intervention, radiological procedure, behavioral intervention, or preventive health care strategy. Clinical trials are challenging, time-consuming, and need careful planning and execution. There are certain requirements for an academic unit to be ready for conducting quality research, especially clinical trials. These include logistical concerns, infrastructure, appropriately trained human resources, conformity with ethical compliances and regulatory compliances as per the laws governing the respective geographical regions. Infrastructure requirements include research division space, robust data archival system, archival of imaging data, laboratory services, information technology division and facilities for the appropriate consenting process. Human resources such as principal investigators, data managers, clinical research assistants and biostatisticians are needed to execute the clinical trial as per the study design. Adherence to ethical and regulatory standards; during the conduct of the clinical trial are imperative. Strict compliance with prevailing governing laws in the country is a prerequisite for a department to get involved in clinical trials. The department also needs to put in place an institutional ethics committee; the composition of which is often governed by regulatory laws. The ethical aspects of the trial undergo a formal scrutiny by an Institute ethics committee that ensures quality care to the patient, and safeguards the patient's rights and privileges. The academic unit of any department forms the core for possible research and pursuit of clinical trials. A department with rich clinical experience and expertise in the filed aids in the execution of quality research. The academic department must consider grant writing and multiple center collaborative research projects in due course of time to further enhance the quality of clinical trials and research output., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Purpose: The use of standalone cages (SAC) and anchored cages (AC) in anterior cervical discectomy and fusion surgery (ACDF) has shown advantage of reduced operative time and lower incidence of dysphagia. However, there is limited literature available comparing the clinical and radiological outcomes of SAC and AC., Methods: We conducted a prospective study for patients undergoing ACDF for cervical radiculopathy or myelopathy. Patient were classified based on the cage used into SAC group and the AC group. Clinical outcomes were assessed using the modified Japanese Orthopedic Association (mJOA) for myelopathy and Neck Disability Index (NDI) and Visual Analogue Scale (VAS) for radiculopathy. Dysphagia was graded as per Bazaz score. Radiologically, global cervical lordosis, segmental lordosis, cage subsidence, and migration were assessed., Results: We analyzed 31 patients in each group with a minimum two year follow-up. The mean VAS improved from 7.9 to 4.56, mean NDI score improved from 27.6 to 19.8, and mean mJOA improved from 10.8 to 11.7 which were statistically significant (p < 0.05); however, no significant difference was noted between the SAC and AC groups. Mean global lordosis improved from 14.4 to 20.3° and mean segmental lordosis improved from 6 to 10.1° at six months and plateaued to 6.9° at final follow up without any significant difference between the groups. The subsidence was statistically more in 12.9% (4/31) in SAC than 6.4% (2/31) in AC., Conclusion: AC showed of lower rates of subsidence while both SAC and AC had comparable clinical outcomes and radiological alignment outcomes., (© 2022. The Author(s) under exclusive licence to SICOT aisbl.)

Integration into host target DNA (tDNA), a hallmark of retroviral replication, is mediated by the intasome, a multimer of integrase (IN) assembled on viral DNA (vDNA) ends. To ascertain aspects of tDNA recognition during integration, we have solved the 3.5 Å resolution cryo-EM structure of the mouse mammary tumor virus (MMTV) strand transfer complex (STC) intasome. The tDNA adopts an A-like conformation in the region encompassing the sites of vDNA joining, which exposes the sugar-phosphate backbone for IN-mediated strand transfer. Examination of existing retroviral STC structures revealed conservation of A-form tDNA in the analogous regions of these complexes. Furthermore, analyses of sequence preferences in genomic integration sites selectively targeted by six different retroviruses highlighted consistent propensity for A-philic sequences at the sites of vDNA joining. Our structure additionally revealed several novel MMTV IN-DNA interactions, as well as contacts seen in prior STC structures, including conserved Pro125 and Tyr149 residues interacting with tDNA. In infected cells, Pro125 substitutions impacted the global pattern of MMTV integration without significantly altering local base sequence preferences at vDNA insertion sites. Collectively, these data advance our understanding of retroviral intasome structure and function, as well as factors that influence patterns of vDNA integration in genomic DNA., (© The Author(s) 2022. Published by Oxford University Press on behalf of Nucleic Acids Research.)

Background: Whole body MRI has been used to evaluate inflammatory lesions associated with axial spondyloarthritis (SpA). These sequences are extensive, time consuming and add to the cost of the investigation. We aimed to determine the utility of selected sequence MRI imaging of the axial skeleton including spine, pelvis and sacroiliac (SI) joints to identify features of (SpA)., Methods: A retrospective study was conducted on 76 patients diagnosed with SpA that underwent a selective sequence MRI imaging of the axial skeleton. The MRI were reported by two musculoskeletal trained radiologists were reviewed. The MRI sequences included whole spine sequences of sagittal STIR (short tau inversion recovery), T1 weighted and T2 weighted sequences. Coronal STIR and T1 weighted images were studied for SI joints and pelvis. The MRI were assessed based on the guidelines outlined by the Assessment of SpondyloArthritis International Society (ASAS) for features of spondylitis, spondylodiscitis, enthesitis, synovitis, capsulitis, bone marrow edema, fatty marrow replacement, erosions and bony ankylosis. Inflammatory lesions were documented in the spine, sacroiliac, facet, hip and costovertebral joints., Results: The mean scan duration was 28 min. SI joint involvement was noted in 74 (97.3%) of patients. The other most prevalent findings were spondylitis in 44 (57.8%) patients, costovertebral joint involvement in 31 (40.7%), facet joint lesions in 32 (42.1%), spondylodiscitis in 21 (27.6%), enthesitis in 13 (17.1%), hip lesions in 16 (21%) and ankylosis in 10 (13.1%)., Conclusions: This selective sequence imaging of the pelvis and spine was able to identify typical lesions of SpA in a shorter time period. Fifty-five percent patients had lesions in the posterior elements including facet joints and costovertbral joints that would be missed on traditional SI joint imaging., Competing Interests: The authors have no relevant financial or non-financial interests to disclose., (© 2022 Delhi Orthopedic Association. All rights reserved.)

Single-particle analysis (SPA) by cryo-electron microscopy (cryo-EM) is now a mainstream technique for high-resolution structural biology. Structure determination by SPA relies upon obtaining multiple distinct views of a macromolecular object vitrified within a thin layer of ice. Ideally, a collection of uniformly distributed random projection orientations would amount to all possible views of the object, giving rise to reconstructions characterized by isotropic directional resolution. However, in reality, many samples suffer from preferentially oriented particles adhering to the air-water interface. This leads to non-uniform angular orientation distributions in the dataset and inhomogeneous Fourier-space sampling in the reconstruction, translating into maps characterized by anisotropic resolution. Tilting the specimen stage provides a generalizable solution to overcoming resolution anisotropy by virtue of improving the uniformity of orientation distributions, and thus the isotropy of Fourier space sampling. The present protocol describes a tilted-stage automated data collection strategy using Leginon, a software for automated image acquisition. The procedure is simple to implement, does not require any additional equipment or software, and is compatible with most standard transmission electron microscopes (TEMs) used for imaging biological macromolecules.

Multisystem inflammatory syndrome in neonates (MIS-N) is hypothesised to be caused either following transplacental transfer of SARS-CoV2 antibodies or antibodies developed in the neonate after infection with SARS-CoV-2. In this paper, we aim to discuss the clinical manifestations, laboratory features, and management of neonates diagnosed with MIS-N. We collated information from five participating hospitals in western India. A cohort of newborn infants presenting with multi-system involvement, along with the presence of SARS-CoV2 antibodies, was identified. Current proposed international diagnostic criteria for MIS-N were used to group the cases into three categories of Most likely, Possible, and Unlikely MIS-N. A total of 20 cases were reported with a diagnosis of MIS-N, all having high titres of SARS CoV2 IgG antibodies and negative for SARS CoV2 antigens. Most likely MIS (n = 5) cases presented with respiratory distress (4/5), hypotension and shock (4/5), and encephalopathy (2/5). Inflammatory markers like CRP (1/5), Procalcitonin (1/5), Ferritin (3/5), D-dimer (4/5), and LDH (2/5) were found to be elevated, and four of them had significantly high levels of proBNP. The majority of them (4/5) responded to immunomodulators, three neonates were discharged home, and two died. Possible MIS infants (n = 9) presented with fever (7/9), respiratory distress (4/9), refusal to feed (6/9), lethargy (5/9), and tachycardia (3/9). ProBNP as a marker of cardiac dysfunction was noted to be elevated in four (4/9) infants, correlating with abnormal echocardiography findings in two. In the Unlikely MIS (n = 6) category, three (3/6) infants presented with respiratory distress, one (1/6) with shock and cardiac dysfunction, and only one (1/6) with fever. All of them had elevated inflammatory markers. However, there were other potential diagnoses that could have been responsible for the clinical scenarios in these six cases.   Conclusion: MIS-N requires a high index of suspicion and should be considered in a neonate presenting with two or more systems involvement, in the presence of SARS-CoV2 antibodies, along with elevated inflammatory markers, once other common neonatal conditions have been ruled out. What is Known: • Severe acute respiratory syndrome coronavirus-2 (SARS-CoV2) associated multisystem inflammatory syndrome in children (MIS-C) is  widely reported in paediatric population, however only few reports of newborn affection. • MIS-C is known to cause by virus-induced post-infective antibody mediated immune dysregulation with severe multi-system affection. What is New: • MIS-N may present with varied clinical manifestations with multi-system involvement of variable severity with milder disease in term and severe disease with cardiac dysfunction in preterm newborns. • Multisystem inflammatory syndrome in newborns (MIS-N) is postulated to occur following immune dysregulation associated with transplacental transfer of SARS-CoV2 antibodies or antibodies developed in the neonate after infection with SARS-CoV-2., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: Presence of supracondylar and periarticular femoral fracture with associated arthritis of knee poses a challenging situation to the orthopaedic surgeon. The results of fixation of fracture in osteoporosis are not very satisfactory and have complications. With fixation alone, they still cannot bear weight on affected leg due to severe disability of osteoarthritis. To make patient walk, conventionally three surgeries in the form of fracture fixation, removal of implant and total knee arthroplasty (TKA) needs to be done in staged manner. We propose a novel management in form of bifold fixation and simultaneous TKA., Methods: Eight cases (6 females, 2 males) of supracondylar femoral fractures with severe osteoarthritis of the knee and osteoporosis were primarily fixed with bifold fixation using SIGN nail ( www.signfracturecare.org ) and locking plate together with simultaneous total knee arthroplasty. There were five cases (2 males and 3 females) of grade 4 (Kellgren-Lawrence grading) osteoarthritis (OA) and three cases (all females) of severe rheumatoid arthritis (RA)., Results: The mean age was 68 years and average time for full weight bearing was 6 days. Radiographic evidence of fracture union was achieved in 16.25 weeks. The mean Knee Society Score (KSS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score at 26 months was 83.13 and 22.13 respectively., Conclusions: Single stage combined bifold osteosynthesis with interlocking nail and locking plate together with total knee arthroplasty helps in one time management of these difficult injuries. It is a cost-effective and economically sound option and gives excellent results with good patient satisfaction., (© 2021. The Author(s).)

The extraterminal (ET) domain of BRD3 is conserved among BET proteins (BRD2, BRD3, BRD4), interacting with multiple host and viral protein-protein networks. Solution NMR structures of complexes formed between the BRD3 ET domain and either the 79-residue murine leukemia virus integrase (IN) C-terminal domain (IN 329-408 ) or its 22-residue IN tail peptide (IN 386-407 ) alone reveal similar intermolecular three-stranded β-sheet formations. 15 N relaxation studies reveal a 10-residue linker region (IN 379-388 ) tethering the SH3 domain (IN 329-378 ) to the ET-binding motif (IN 389-405 ):ET complex. This linker has restricted flexibility, affecting its potential range of orientations in the IN:nucleosome complex. The complex of the ET-binding peptide of the host NSD3 protein (NSD3 148-184 ) and the BRD3 ET domain includes a similar three-stranded β-sheet interaction, but the orientation of the β hairpin is flipped compared with the two IN:ET complexes. These studies expand our understanding of molecular recognition polymorphism in complexes of ET-binding motifs with viral and host proteins., Competing Interests: Declaration of interests G.T.M. is a founder of Nexomics Biosciences, Inc. G.L. is chief scientific officer and director of Nexomics Biosciences, Inc. The remaining authors declare no competing interests., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

A systematic and quantitative evaluation of cryo-EM maps is necessary to judge their quality and to capture all possible sources of error. A single value for global resolution is insufficient to accurately describe the quality of a reconstructed density. We describe the estimation and evaluation of two additional resolution measures, local and directional resolution, using methods based on the Fourier shell correlation (FSC). We apply the protocol to samples that encompass different types of pathologies a user is expected to encounter and provide analyses on how to interpret the output files and resulting maps. Implementation of these tools will facilitate density interpretation and can guide the user in adapting their experiments to improve the quality of cryo-EM maps, and by extension atomic models.

A 14-year-old girl presented with an insidious onset of left hip pain, limp, and intermittent fever for a 3-month duration. Patient had a history of toe walking since childhood which continued into adolescence. On radiographic investigations, she was found to have a dysplastic hip with fluid collection around the hip which was surgically drained. The microbiological investigations proved the presence of Mycobacterium tuberculosis (TB). Accordingly, she was started on anti-TB chemotherapy as per drug sensitivity. TB infection in a previously neglected dysplastic hip is not reported as per our knowledge and poses unique diagnostic and management difficulties., Competing Interests: None of the following authors or any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this article: Dr. Aiyer, Dr. Raj, Dr. Shah, Dr. Marathe, and Dr. Sujith., (Copyright © 2020 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Orthopaedic Surgeons.)

Murine leukemia virus (MLV) integrase (IN) lacking the C-terminal tail peptide (TP) loses its interaction with the host bromodomain and extraterminal (BET) proteins and displays decreased integration at promoter/enhancers and transcriptional start sites/CpG islands. MLV lacking the IN TP via an altered open reading frame was used to infect tumorigenesis mouse model (MYC/Runx2) animals to observe integration patterns and phenotypic effects, but viral passage resulted in the restoration of the IN TP through small deletions. Mice subsequently infected with an MLV IN lacking the TP coding sequence (TP-) showed an improved median survival by 15 days compared to wild type (WT) MLV infection. Recombination with polytropic endogenous retrovirus (ERV), Pmv20, was identified in seven mice displaying both fast and slow tumorigenesis, highlighting the strong selection within the mouse to maintain the full-length IN protein. Mapping the genomic locations of MLV in tumors from an infected mouse with no observed recombination with ERVs, TP-16, showed fewer integrations at TSS and CpG islands, compared to integrations observed in WT tumors. However, this mouse succumbed to the tumor in relatively rapid fashion (34 days). Analysis of the top copy number integrants in the TP-16 tumor revealed their proximity to known MLV common insertion site genes while maintaining the MLV IN TP- genotype. Furthermore, integration mapping in K562 cells revealed an insertion preference of MLV IN TP- within chromatin profile states associated with weakly transcribed heterochromatin with fewer integrations at histone marks associated with BET proteins (H3K4me1/2/3, and H3K27Ac). While MLV IN TP- showed a decreased overall rate of tumorigenesis compared to WT virus in the MYC/Runx2 model, MLV integration still occurred at regions associated with oncogenic driver genes independently from the influence of BET proteins, either stochastically or through trans-complementation by functional endogenous Gag-Pol protein., Competing Interests: The authors have declared that no competing interests exist.

Single-particle cryogenic electron microscopy (cryo-EM) provides a powerful methodology for structural biologists, but the resolutions typically attained with experimentally determined structures have lagged behind microscope capabilities. Here, we exploit several technical advances to improve resolution, including per-particle contrast transfer function (CTF) refinement and correction for Ewald sphere curvature. The latter is demonstrated with several experimental samples and should become more standard as resolutions increase or at lower microscope accelerating voltages. The combined application of the described methods to micrographs recorded on a Titan Krios enables structure determination at ~1.86-Å resolution of an adeno-associated virus serotype 2 variant (AAV2), an important gene-delivery vehicle. The resulting structural details provide an improved model for understanding the biology of AAV that will guide future vector development for gene therapy.

Purpose: To develop a classification based on the technical complexity encountered during pedicle screw insertion and to evaluate the performance of AIRO ® CT navigation system based on this classification, in the clinical scenario of complex spinal deformity., Materials and Methods: 31 complex spinal deformity correction surgeries were prospectively analyzed for performance of AIRO ® mobile CT-based navigation system. Pedicles were classified according to complexity of insertion into five types. Analysis was performed to estimate the accuracy of screw placement and time for screw insertion. Breach greater than 2 mm was considered for analysis., Results: 452 pedicle screws were inserted (T1-T6: 116; T7-T12: 171; L1-S1: 165). The average Cobb angle was 68.3° (range 60°-104°). We had 242 grade 2 pedicles, 133 grade 3, and 77 grade 4, and 44 pedicles were unfit for pedicle screw insertion. We noted 27 pedicle screw breach (medial: 10; lateral: 16; anterior: 1). Among lateral breach (n = 16), ten screws were planned for in-out-in pedicle screw insertion. Among lateral breach (n = 16), ten screws were planned for in-out-in pedicle screw insertion. Average screw insertion time was 1.76 ± 0.89 min. After accounting for planned breach, the effective breach rate was 3.8% resulting in 96.2% accuracy for pedicle screw placement., Conclusion: This classification helps compare the accuracy of screw insertion in range of conditions by considering the complexity of screw insertion. Considering the clinical scenario of complex pedicle anatomy in spinal deformity AIRO ® navigation showed an excellent accuracy rate of 96.2%.

The retroviral integrase (IN) carries out the integration of a dsDNA copy of the viral genome into the host DNA, an essential step for viral replication. All IN proteins have three general domains, the N-terminal domain (NTD), the catalytic core domain, and the C-terminal domain. The NTD includes an HHCC zinc finger-like motif, which is conserved in all retroviral IN proteins. Two crystal structures of Moloney murine leukemia virus (M-MuLV) IN N-terminal region (NTR) constructs that both include an N-terminal extension domain (NED, residues 1-44) and an HHCC zinc-finger NTD (residues 45-105), in two crystal forms are reported. The structures of IN NTR constructs encoding residues 1-105 (NTR 1-105 ) and 8-105 (NTR 8-105 ) were determined at 2.7 and 2.15 Å resolution, respectively and belong to different space groups. While both crystal forms have similar protomer structures, NTR 1-105 packs as a dimer and NTR 8-105 packs as a tetramer in the asymmetric unit. The structure of the NED consists of three anti-parallel β-strands and an α-helix, similar to the NED of prototype foamy virus (PFV) IN. These three β-strands form an extended β-sheet with another β-strand in the HHCC Zn 2+ binding domain, which is a unique structural feature for the M-MuLV IN. The HHCC Zn 2+ binding domain structure is similar to that in HIV and PFV INs, with variations within the loop regions. Differences between the PFV and MLV IN NEDs localize at regions identified to interact with the PFV LTR and are compared with established biochemical and virological data for M-MuLV. Proteins 2017; 85:647-656. © 2016 Wiley Periodicals, Inc., (© 2017 Wiley Periodicals, Inc.)

Designing bioresponsive nanocarriers for controlled and efficient intracellular drug release for cancer therapy is a major thrust area in nanomedicine. With recent recognition by the US FDA as a safe material for human trials, mesoporous silica nanoparticles (MSNPs) are being extensively explored as promising theranostic agents. Green fluorescent carbon quantum dots (CQDs), though known as possible alternatives for their more toxic and relatively less efficient predecessors, are less known as gate keepers for drug release control. We report for the first time an efficient bioresponse of CQDs when judiciously designed using glutathione cleavable (redox responsive) disulphide bonds. When the anticancer drug doxorubicin loaded MSNPs are capped with these CQDs, they display promising drug release control on exposure to a mimicked intracellular cancer environment. Their dual functionality is well established with good control on preventing the premature release and exceptional bio-imaging of HeLa cancer cells. Fluorescence images prove selective targeting of HeLa cells by overexpression of folate receptors from the surface functionalised folic acid ligand. Extensive characterisation using XRD, TEM, BET analysis, drug loading tests, drug release kinetics, MTT assay and fluoroscence cell imaging helps in understanding the multifunctionalities of the successful design, extending its scope with exciting prospects towards non-invasive targeted drug delivery and bio-imaging for effective cancer diagnosis and treatment.

We report alterations to the murine leukemia virus (MLV) integrase (IN) protein that successfully result in decreasing its integration frequency at transcription start sites and CpG islands, thereby reducing the potential for insertional activation. The host bromo and extraterminal (BET) proteins Brd2, 3 and 4 interact with the MLV IN protein primarily through the BET protein ET domain. Using solution NMR, protein interaction studies, and next generation sequencing, we show that the C-terminal tail peptide region of MLV IN is important for the interaction with BET proteins and that disruption of this interaction through truncation mutations affects the global targeting profile of MLV vectors. The use of the unstructured tails of gammaretroviral INs to direct association with complexes at active promoters parallels that used by histones and RNA polymerase II. Viruses bearing MLV IN C-terminal truncations can provide new avenues to improve the safety profile of gammaretroviral vectors for human gene therapy., (© The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.)

The "condylus tertius" or the "third occipital condyle" is an embryological remnant of the proatlas sclerotome. Anatomically, it is attached to the basion and often articulates with the anterior arch of the atlas and the odontoid apex; hence, it is also called the "median occipital condyle". It is a rare anomaly of the cranio-vertebral junction (CVJ) that can lead to instability and compression of important surrounding neurovascular structures. We report a case of a 16-year-old boy who presented with suboccipital neck pain, torticollis and right sided hemiparesis. Plain radiographs revealed an increased atlanto-dental interspace (ADI) with a retroflexed odontoid. Open mouth view showed asymmetry of the articular processes of the atlas with respect to the dens. Computed tomography (CT) of the CVJ delineated the third occipital condyle. Furthermore, on dynamic CT study, a type 3 atlanto-axial rotatory fixation (AARF) was clearly demonstrated. Magnetic resonance imaging (MRI) of the CVJ revealed severe right-sided spinal cord compression by the retroflexed and rightward deviated dens. It also revealed disruption of the left alar and transverse ligaments. The patient was treated with 8 weeks of cranial traction and reasonable alignment was obtained. This was followed by C1-C2 lateral mass screw fixation and C1-C2 interlaminar wiring to maintain the alignment. A review of the literature did not reveal any cases of condylus tertius associated with non-traumatic AARF. An accurate knowledge of the embryology and imaging features of this rare CVJ anomaly is useful in the prompt diagnosis and management of such patients.

Retroviral vectors derived from the murine leukemia virus (MuLV) are widely used as the starting material in the development of vectors for gene therapy and critical in answering questions relating to viral pathogenesis. The p30 capsid (CA) is the major viral core protein and an internal group antigen in MuLV. In this study, an enzyme-linked immunosorbent assay (ELISA) was developed for quantitation of MuLV infectious particles with p30 CA core antigen protein. The ELISA was developed using several goat-polyclonal serum against MuLV p30 generated by the NCI as primary antibody and a rat-monoclonal antibody to CA available from ATCC. The MuLV p30 CA antigen was standardized against recombinant MuLV p30 CA expressed from bacteria. The assay is sensitive, accurate and linear within a defined concentration range of CA. Comparison with different MuLV quantitative methods including reporter gene transfer, reverse transcriptase activity assay, and viral RNA quantitative PCR, showed this ELISA protocol to be highly quantifiable within defined ranges, which can be correlated with infectious viral titer., (Copyright © 2013 Elsevier B.V. All rights reserved.)