Search

Transcriptional elongation by RNA polymerase II (RNAPII) through chromatin is a dynamic and highly regulated step of eukaryotic gene expression. A combination of transcript elongation factors (TEFs) including modulators of RNAPII activity and histone chaperones facilitate efficient transcription on nucleosomal templates. Biochemical and genetic analyses, primarily performed in Arabidopsis, provided insight into the contribution of TEFs to establish gene expression patterns during plant growth and development. In addition to summarising the role of TEFs in plant gene expression, we emphasise in our review recent advances in the field. Thus, mechanisms are presented how aberrant intragenic transcript initiation is suppressed by repressing transcriptional start sites within coding sequences. We also discuss how transcriptional interference of ongoing transcription with neighbouring genes is prevented. Moreover, it appears that plants make no use of promoter-proximal RNAPII pausing in the way mammals do, but there are nucleosome-defined mechanism(s) that determine the efficiency of mRNA synthesis by RNAPII. Accordingly, a still growing number of processes related to plant growth, development and responses to changing environmental conditions prove to be regulated at the level of transcriptional elongation., (© 2023 The Authors. The Plant Journal published by Society for Experimental Biology and John Wiley & Sons Ltd.)

Various transcript elongation factors (TEFs) including modulators of RNA polymerase II (RNAPII) activity and histone chaperones tune the efficiency of transcription in the chromatin context. TEFs are involved in establishing gene expression patterns during growth and development in Arabidopsis, while little is known about the genomic distribution of the TEFs and the way they facilitate transcription. We have mapped the genome-wide occupancy of the elongation factors SPT4-SPT5, PAF1C and FACT, relative to that of elongating RNAPII phosphorylated at residues S2/S5 within the carboxyterminal domain. The distribution of SPT4-SPT5 along transcribed regions closely resembles that of RNAPII-S2P, while the occupancy of FACT and PAF1C is rather related to that of RNAPII-S5P. Under transcriptionally challenging heat stress conditions, mutant plants lacking the corresponding TEFs are differentially impaired in transcript synthesis. Strikingly, in plants deficient in PAF1C, defects in transcription across intron/exon borders are observed that are cumulative along transcribed regions. Upstream of transcriptional start sites, the presence of FACT correlates with nucleosomal occupancy. Under stress conditions FACT is particularly required for transcriptional upregulation and to promote RNAPII transcription through +1 nucleosomes. Thus, Arabidopsis TEFs are differently distributed along transcribed regions, and are distinctly required during transcript elongation especially upon transcriptional reprogramming., (© The Author(s) 2023. Published by Oxford University Press on behalf of Nucleic Acids Research.)

Elongation factors modulate the efficiency of mRNA synthesis by RNA polymerase II (RNAPII) in the context of chromatin, thus contributing to implement proper gene expression programmes. The zinc-finger protein elongation factor 1 (ELF1) is a conserved transcript elongation factor (TEF), whose molecular function so far has not been studied in plants. Using biochemical approaches, we examined the interaction of Arabidopsis ELF1 with DNA and histones in vitro and with the RNAPII elongation complex in vivo. In addition, cytological assays demonstrated the nuclear localisation of the protein, and by means of double-mutant analyses, interplay with genes encoding other elongation factors was explored. The genome-wide distribution of ELF1 was addressed by chromatin immunoprecipitation. ELF1 isolated from Arabidopsis cells robustly copurified with RNAPII and various other elongation factors including SPT4-SPT5, SPT6, IWS1, FACT and PAF1C. Analysis of a CRISPR-Cas9-mediated gene editing mutant of ELF1 revealed distinct genetic interactions with mutants deficient in other elongation factors. Moreover, ELF1 associated with genomic regions actively transcribed by RNAPII. However, ELF1 occupied only c. 33% of the RNAPII transcribed loci with preference for inducible rather than constitutively expressed genes. Collectively, these results establish that Arabidopsis ELF1 shares several characteristic attributes with RNAPII TEFs., (© 2023 The Authors. New Phytologist © 2023 New Phytologist Foundation.)

In addition to the stage of transcriptional initiation, the production of mRNAs is regulated during elongation. Accordingly, the synthesis of mRNAs by RNA polymerase II (RNAPII) in the chromatin context is modulated by various transcript elongation factors. TFIIS is an elongation factor that stimulates the transcript cleavage activity of RNAPII to reactivate stalled elongation complexes at barriers to transcription including nucleosomes. Since Arabidopsis tfIIs mutants grow normally under standard conditions, we have exposed them to heat stress (HS), revealing that tfIIs plants are highly sensitive to elevated temperatures. Transcriptomic analyses demonstrate that particularly HS-induced genes are expressed at lower levels in tfIIs than in wildtype. Mapping the distribution of elongating RNAPII uncovered that in tfIIs plants RNAPII accumulates at the +1 nucleosome of genes that are upregulated upon HS. The promoter-proximal RNAPII accumulation in tfIIs under HS conditions conforms to that observed upon inhibition of the RNAPII transcript cleavage activity. Further analysis of the RNAPII accumulation downstream of transcriptional start sites illustrated that RNAPII stalling occurs at +1 nucleosomes that are depleted in the histone variant H2A.Z upon HS. Therefore, assistance of early transcript elongation by TFIIS is required for reprogramming gene expression to establish plant thermotolerance., Competing Interests: Conflict of Interest The authors declare no conflicts of interests., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Transcript elongation by RNA polymerase II (RNAPII) is dynamic and highly regulated, thereby contributing to the implementation of gene expression programs during plant development or in response to environmental cues. The heterohexameric polymerase-associated factor 1 complex (PAF1C) stabilizes the RNAPII elongation complex promoting efficient transcript synthesis. In addition, PAF1C links transcriptional elongation with various post-translational histone modifications at transcribed loci. We have exposed Arabidopsis mutants deficient in the PAF1C subunits ELF7 or CDC73 to elevated NaCl concentrations to provoke a transcriptional response. The growth of elf7 plants was reduced relative to that of wildtype under these challenging conditions, whereas cdc73 plants exhibited rather enhanced tolerance. Profiling of the transcriptional changes upon NaCl exposure revealed that cdc73 responded similar to wildtype. Relative to wildtype and cdc73 , the transcriptional response of elf7 plants was severely reduced in accord with their greater susceptibility to NaCl. The data also imply that CDC73 is more relevant for the transcription of longer genes. Despite the fact that both ELF7 and CDC73 are part of PAF1C the strikingly different transcriptional response of the mutants upon NaCl exposure suggests that the subunits have (partially) specific functions., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer IL declared a past co-authorship with one of the authors KDG to the handling editor., (Copyright © 2022 Obermeyer, Stöckl, Schnekenburger, Moehle, Schwartz and Grasser.)

Interleukin (IL)-4 plays a central role in the initiation of a type 2 T helper cell (Th2) response, which leads to non-healing and progressive infections with the protozoan parasite Leishmania ( L. ) major . Here, we tested the hypothesis that type 2 innate lymphoid cells (ILC2), which promote the development of Th2 cells, form an important source of IL-4 early after intradermal or subcutaneous L. major infection. Lineage-marker negative CD90.2 + CD127 + PD1 - ILC2 were readily detectable in the ear or foot skin, but hardly in the draining lymph nodes of both naïve and L. major -infected self-healing C57BL/6 and non-healing BALB/c mice and made up approximately 20% to 30% of all CD45 + SiglecF - cells. Dermal ILC2 of C57BL/6 mice expressed the inducible T cell-costimulator (ICOS, CD278), whereas BALB/C ILC2 were positive for the stem cell antigen (Sca)-1. Within the first 5 days of infection, the absolute numbers of ILC2 did not significantly change in the dermis, which is in line with the unaltered expression of cytokines activating (IL-18, IL-25, IL-33, TSLP) or inhibiting ILC2 (IL-27, IFN-γ). At day 5 to 6 post infection, we observed an upregulation of IL-4, but not of IL-5, IL-10 or IL-13 mRNA. Using IL-4-reporter (4get) mice, we found that the production of IL-4 by C57BL/6 or BALB/c mice was largely restricted to CD45 + SiglecF + cells of high granularity, i.e., eosinophils. From these data, we conclude that eosinophils, but not ILC2, are a major innate source of IL-4 at the skin site of L. major infection.

The heterodimeric histone chaperone FACT, consisting of SSRP1 and SPT16, contributes to dynamic nucleosome rearrangements during various DNA-dependent processes including transcription. In search of post-translational modifications that may regulate the activity of FACT, SSRP1 and SPT16 were isolated from Arabidopsis cells and analysed by mass spectrometry. Four acetylated lysine residues could be mapped within the basic C-terminal region of SSRP1, while three phosphorylated serine/threonine residues were identified in the acidic C-terminal region of SPT16. Mutational analysis of the SSRP1 acetylation sites revealed only mild effects. However, phosphorylation of SPT16 that is catalysed by protein kinase CK2, modulates histone interactions. A non-phosphorylatable version of SPT16 displayed reduced histone binding and proved inactive in complementing the growth and developmental phenotypes of spt16 mutant plants. In plants expressing the non-phosphorylatable SPT16 version we detected at a subset of genes enrichment of histone H3 directly upstream of RNA polymerase II transcriptional start sites (TSSs) in a region that usually is nucleosome-depleted. This suggests that some genes require phosphorylation of the SPT16 acidic region for establishing the correct nucleosome occupancy at the TSS of active genes., (© The Author(s) 2022. Published by Oxford University Press on behalf of Nucleic Acids Research.)

Postpartum hemorrhage (PPH) is a leading cause of maternal morbidity and mortality worldwide. Mitigation of PPH is dependent on identification of risk, readiness, timely identification of hemorrhage, accurate determination of blood loss, and effective treatment. Perinatal nurses must be prepared to participate in all these aspects of care, including the use of tranexamic acid, an antifibrinolytic agent that has more recently been added to the pharmacologic agents used to reduce blood loss associated with hemorrhage. The purpose of this article is to identify the nurse's role in the management of PPH and to introduce the use of tranexamic acid in PPH management as part of the nurse's role in implementing best practices for PPH., (Copyright © 2022. Published by Elsevier Inc.)

Tranexamic acid (TXA) is an antifibrinolytic pharmacologic agent with demonstrated effectiveness for reducing the incidence of death from blood loss following trauma and major surgery. In intrapartum care, TXA is being used in in conjunction with uterotonic agents to treat postpartum hemorrhage (PPH). Based on the findings of the WOMAN trial that found TXA reduced maternal death due to PPH, the World Health Organization recommends that TXA be part of the standard comprehensive PPH treatment package, and US professional organizations recognize its use as adjunctive treatment for PPH. Evidence suggests that TXA used prophylactically in the setting of cesarean birth may decrease blood loss and the incidence of PPH. There is limited evidence for prophylactic use of TXA in women of all risk categories following vaginal birth but prophylactic use in women who have an a priori risk for PPH is being investigated. This article presents a case in which a midwife identifies a woman in active labor who has significant risk factors for PPH. In consultation with the collaborating obstetrician, TXA is given early during the third stage of labor in addition to the recommended components of active management for the purpose of preventing PPH., (© 2020 The Authors. Journal of Midwifery & Women's Health published by Wiley Periodicals, Inc. on behalf of American College of Nurse Midwives (ACNM).)

Cryptococcus neoformans is an opportunistic fungal pathogen preferentially causing disease in immunocompromised individuals such as organ-transplant-recipients, patients receiving immunosuppressive medications or, in particular, individuals suffering from HIV infection. Numerous studies clearly indicated that the control of C. neoformans infections is strongly dependent on a prototypic type 1 immune response and classical macrophage activation, whereas type 2-biased immunity and alternative activation of macrophages has been rather implicated in disease progression and detrimental outcomes. However, little is known about regulatory pathways modulating and balancing immune responses during early phases of pulmonary cryptococcosis. Here, we analyzed the role of group 2 innate lymphoid cells (ILC2s) for the control of C. neoformans infection. Using an intranasal infection model with a highly virulent C. neoformans strain, we found that ILC2 numbers were strongly increased in C. neoformans -infected lungs along with induction of a type 2 response. Mice lacking ILC2s due to conditional deficiency of the transcription factor RAR-related orphan receptor alpha (Rora) displayed a massive downregulation of features of type 2 immunity as reflected by reduced levels of the type 2 signature cytokines IL-4, IL-5, and IL-13 at 14 days post-infection. Moreover, ILC2 deficiency was accompanied with increased type 1 immunity and classical macrophage activation, while the pulmonary numbers of eosinophils and alternatively activated macrophages were reduced in these mice. Importantly, this shift in pulmonary macrophage polarization in ILC2-deficient mice correlated with improved fungal control and prolonged survival of infected mice. Conversely, adoptive transfer of ILC2s was associated with a type 2 bias associated with less efficient anti-fungal immunity in lungs of recipient mice. Collectively, our date indicate a non-redundant role of ILC2 in orchestrating myeloid anti-cryptococcal immune responses toward a disease exacerbating phenotype., (Copyright © 2020 Kindermann, Knipfer, Obermeyer, Müller, Alber, Bogdan, Schleicher, Neurath and Wirtz.)

Experimental cutaneous leishmaniasis of mice is a valuable model to study the immune response to the protozoan pathogen Leishmania and to define mechanisms of parasite control and resolution of inflammation as well as of parasite evasion and chronicity of disease. In addition, over many years Leishmania-infected mice have been successfully used to analyze the function of newly discovered immune cell types, transcription factors, cytokines, and effector mechanisms in vivo. In this chapter we present detailed protocols for the culture, propagation, and inoculation of Leishmania promastigotes, the monitoring of the course of cutaneous infection, the determination of the tissue parasite burden and for the phenotyping of the ensuing immune response. The focus lies on the L. major mouse model, but an overview on other established models of murine cutaneous leishmaniasis is also provided.

Thiolutin is a disulfide-containing antibiotic and anti-angiogenic compound produced by Streptomyces. Its biological targets are not known. We show that reduced thiolutin is a zinc chelator that inhibits the JAB1/MPN/Mov34 (JAMM) domain-containing metalloprotease Rpn11, a deubiquitinating enzyme of the 19S proteasome. Thiolutin also inhibits the JAMM metalloproteases Csn5, the deneddylase of the COP9 signalosome; AMSH, which regulates ubiquitin-dependent sorting of cell-surface receptors; and BRCC36, a K63-specific deubiquitinase of the BRCC36-containing isopeptidase complex and the BRCA1-BRCA2-containing complex. We provide evidence that other dithiolopyrrolones also function as inhibitors of JAMM metalloproteases.

Objectives: Processing of horizontal face cues has been shown to be an important element in face recognition of adults aged up to 30 years. In contrast, horizontally aligned facial features do not appear to contribute to older adults' (60-75 years) recognition in a similar way. To this end, we investigated potential learning effects on the ability to recognize faces based on horizontal features. Previous research suggests face recognition based on all face information experiences an accelerated decline after the age of 70. However, recognition based only on horizontal face information has not yet been studied in old age (75+ years of age). Thus, we investigated whether older adults (aged up to as well as starting at 75 years) can learn to recognize faces based on horizontal face cues alone., Method: One younger and two older adult groups (20-30, 60-75, and 75+ years) were familiarized with a high and a low amount of previously unfamiliar faces-some containing all face cues and others containing only horizontal face cues (reduced information). Subsequently, all groups received a recognition test., Results: Repeated learning increased natural face recognition for all three age groups when all face cues were available. However, increases in face recognition were only observed for younger adults when horizontal face cued were only available., Discussion: The importance of horizontally aligned spatial frequencies for recognizing human faces is lessened before the age of 60 (and plateaus thereon), whereas recognition of stimuli containing all face cues is still capable of improvement.

Horizontal information, as a result of a selective filtering process, is essential in younger adults' (YA) ability to recognize human faces. Obermeyer et al. (2012) recently reported impaired recognition of faces with horizontal information in older adults (OA) suggesting age-variant processing. Two yet unconsidered factors (stimulus age and exposure duration) that may have influenced previous results, were investigated in this study. Forty-seven YA (18-35 years) and 49 OA (62-83 years) were tested in a 2 × 2 × 2 × 2 mixed design with the between-subjects factors age group (YA vs. OA) and stimulus age (young faces vs. older faces) and the within-subjects factors filter [filtered (HF) faces vs. unfiltered faces (UF)] and exposure duration (0.8 s vs. 8 s). Subjects were presented morph videos between pairs of faces: a starting face gradually merged into either the previously encoded target face or a control face. As expected, results showed an increase in recognition sensitivity ( d' ) with longer exposure duration in YA with both younger and older HF faces. OA, however, were unable to recognize filtered young faces not even with increased exposure duration. Furthermore, only elderly participants showed more accurate recognition with faces of their own age relative to other-age faces (own-age bias, OAB). For YA no OAB was observed. Filtered face recognition was significantly correlated with unfiltered recognition in YA but not in OA. It is concluded, that processing of horizontal information changes at a higher age. Presenting filtered or unfiltered faces both targets convergent face-specific processing only in YA but not in OA.

Neutralization or deletion of tumor necrosis factor (TNF) causes loss of control of intracellular pathogens in mice and humans, but the underlying mechanisms are incompletely understood. Here, we found that TNF antagonized alternative activation of macrophages and dendritic cells by IL-4. TNF inhibited IL-4-induced arginase 1 (Arg1) expression by decreasing histone acetylation, without affecting STAT6 phosphorylation and nuclear translocation. In Leishmania major-infected C57BL/6 wild-type mice, type 2 nitric oxide (NO) synthase (NOS2) was detected in inflammatory dendritic cells or macrophages, some of which co-expressed Arg1. In TNF-deficient mice, Arg1 was hyperexpressed, causing an impaired production of NO in situ. A similar phenotype was seen in L. major-infected BALB/c mice. Arg1 deletion in hematopoietic cells protected these mice from an otherwise lethal disease, although their disease-mediating T cell response (Th2, Treg) was maintained. Thus, deletion or TNF-mediated restriction of Arg1 unleashes the production of NO by NOS2, which is critical for pathogen control., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)

Recent psychophysical research supports the notion that horizontal information of a face is primarily important for facial identity processes. Even though this has been demonstrated to be valid for young adults, the concept of horizontal information as primary informative source has not yet been applied to older adults' ability to correctly identify faces. In the current paper, the role different filtering methods might play in an identity processing task is examined for young and old adults, both taken from student populations. Contrary to most findings in the field of developmental face perception, only a near-significant age effect is apparent in upright and un-manipulated presentation of stimuli, whereas a bigger difference between age groups can be observed for a condition which removes all but horizontal information of a face. It is concluded that a critical feature of human face perception, the preferential processing of horizontal information, is less efficient past the age of 60 and is involved in recognition processes that undergo age-related decline usually found in the literature.