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This article reviews the developments related to Streptomyces chitinases regulation and their post translational modifications. Chitinases are enzymes which cleave chitin, a polymer of N-acetylglucosamine to its monomer. Bacteria produce chitinases to fulfil their nutritional needs since by-products of chitin degradation can serve as a source of carbon and nitrogen. Chitinolytic bacteria such as Streptomyces produce multiple chitinases which act synergistically to degrade crystalline form of chitin. Streptomyces are one of the major producers of chitinases in the soil. Every Streptomyces genome sequenced till date has multiple genes for chitinases. The chitinases resulting from proteolytic cleavage have different specific activities and binding efficiency. Both of the above mentioned factors contribute to complexity of the chitinolytic system. Two component systems (TCS) are the predominant signal transduction system in bacteria that regulate a wide variety of behaviours as well as fundamental processes such as metabolism and motility. Bacteria generally use two-component signal transduction pathways to couple environmental stimuli to adaptive responses. Apart from the generalized behaviours they also regulate specialised processes such as development and virulence. Thus this review focuses on the two component systems of Streptomyces, their mechanism of action, regulation of chitinases by TCS and post-translational modifications.

Growth hormone deficiency affects roughly between one in 3000 and one in 4000 children with most instances of growth hormone deficiency being idiopathic. Growth hormone deficiency can also be associated with genetic diseases or chromosome abnormalities. Association of growth hormone deficiency together with hypothalamic-pituitary axis malformation and Cat-Eye syndrome is a very rare condition. We report a family with two brothers presenting with growth delay due to a growth hormone deficiency associated with a polymalformation syndrome. They both displayed pre-auricular pits and tags, imperforate anus and Duane retraction syndrome. Both parents and a third unaffected son displayed normal growth pattern. Cerebral MRI showed a hypothalamic-pituitary axis malformation in the two affected brothers. Cytogenetic studies revealed a type I small supernumerary marker chromosome derived from chromosome 22 resulting in a tetrasomy 22pter-22q11.21 characteristic of the Cat-Eye syndrome. The small supernumerary marker chromosome was present in the two affected sons and the mother in a mosaic state. Patients with short stature due to growth hormone deficiency should be evaluated for chromosomal abnormality. Family study should not be underestimated.

Stormorken syndrome is a rare autosomal dominant disorder characterized by a phenotype that includes miosis, thrombocytopenia/thrombocytopathy with bleeding time diathesis, intellectual disability, mild hypocalcemia, muscle fatigue, asplenia, and ichthyosis. Using targeted sequencing and whole-exome sequencing, we identified the c.910CT transition in a STIM1 allele (p.R304W) only in patients and not in their unaffected family members. STIM1 encodes stromal interaction molecule 1 protein (STIM1), which is a finely tuned endoplasmic reticulum Ca(2+) sensor. The effect of the mutation on the structure of STIM1 was investigated by molecular modeling, and its effect on function was explored by calcium imaging experiments. Results obtained from calcium imaging experiments using transfected cells together with fibroblasts from one patient are in agreement with impairment of calcium homeostasis. We show that the STIM1 p.R304W variant may affect the conformation of the inhibitory helix and unlock the inhibitory state of STIM1. The p.R304W mutation causes a gain of function effect associated with an increase in both resting Ca(2+) levels and store-operated calcium entry. Our study provides evidence that Stormorken syndrome may result from a single-gene defect, which is consistent with Mendelian-dominant inheritance.

Pre-BCR acts as a critical checkpoint in B cell development. However, its signalling cascade still remains indistinctly characterised in human. We investigated pre-BCR signalling pathway to examine its regulation in normal primary pre-B lymphocytes and pre-B cell lines. In cell lines, early signalling events occurring after pre-BCR stimulation include phosphorylation of Lyn, Blk and Syk together with ZAP70, Btk, Vav, PLC-γ2 and various adaptor proteins, such as BLNK, LAB, LAT and SLP-76. Further downstream, these molecules induced activation of the PI3K/AKT and MAP-kinase resulting in an augmentation of canonical NF-κB pathways and cFos/AP1 activation. PI3K and MAPK exerted opposing effects on the pre-BCR-induced activation of the canonical NF-κB and c-Fos/AP1 pathways. Immediate nuclear export of FoxO3A and delayed import of IRF4 were additional events observed after pre-BCR crosslinking in primary cells. Pre-BCR-induced down-regulation of Rag1, Rag2, E2A and Pax5 transcripts occurred in a PI3K-dependent manner. Finally we bring evidence that pre-BCR stimulation or co stimulation with CD19 enhances cell cycle signal.

// Hicham Bouhlal 1, 2 , Hakim Ouled-Haddou 1, * , Veronique Debuysscher 1, * , Amrathlal Rabbind Singh 1 , Christele Ossart 1, 2 , Aline Reignier 1, 2 , Hakim Hocini 3 , Gregory Fouquet 1 , Mohammed Al Baghami 1, 2 , Melanie Simoes Eugenio 1 , Eric Nguyen-Khac 4 , Jean-Marc Regimbeau 5 , Ingrid Marcq 1 1 Centre Universitaire de Recherche en Sante CURS, CAP-Sante (FED 4231), Universite de Picardie Jules Verne, CHU Sud, Amiens, France 2 Service d’Hematologie Clinique et de Therapie Cellulaire Centre Hospitalier Universitaire Sud, Amiens, France 3 IMRB, Equipe 16, Genomique Medicale, UFR de Medecine, Creteil, France 4 Service Hepato-Gastroenterologie, Centre Hospitalier Universitaire Sud, Amiens, France 5 Service de Chirurgie Digestive Centre Hospitalier Universitaire Sud, Amiens, France * These authors contributed equally to this work Correspondence to: Hicham Bouhlal, e-mail: hicham.bouhlal@u-picardie.fr Amrathlal Rabbind Singh, e-mail: rabbind@gmail.com Ingrid Marcq, e-mail: ingrid.marcq@u-picardie.fr Keywords: SLAMF3, HCC, retinoblastoma factor RB, polo-like kinase 1 (PLK1), mitosis Received: June 18, 2015 Accepted: December 09, 2015 Published: January 20, 2016 ABSTRACT Polo-like kinase PLK1 is a cell cycle protein that plays multiple roles in promoting cell cycle progression. Among the many roles, the most prominent role of PLK1 is to regulate the mitotic spindle formation checkpoint at the M-phase. Recently we reported the expression of SLAMF3 in Hepatocytes and show that it is down regulated in tumor cells of hepatocellular carcinoma (HCC). We also show that the forced high expression level of SLAMF3 in HCC cells controls proliferation by inhibiting the MAPK ERK/JNK and the mTOR pathways. In the present study, we provide evidence that the inhibitory effect of SLAMF3 on HCC proliferation occurs through Retinoblastoma (RB) factor and PLK1-dependent pathway. In addition to the inhibition of MAPK ERK/JNK and the mTOR pathways, expression of SLAMF3 in HCC retains RB factor in its hypophosphorylated active form, which in turn inactivates E2F transcription factor, thereby repressing the expression and activation of PLK1. A clear inverse correlation was also observed between SLAMF3 and PLK expression in patients with HCC. In conclusion, the results presented here suggest that the tumor suppressor potential of SLAMF3 occurs through activation of RB that represses PLK1. We propose that the induction of a high expression level of SLAMF3 in cancerous cells could control cellular mitosis and block tumor progression.

We have identified a deletion of 125 bp (α-α(Δ125)) (NG_000006.1: g.37040_37164del) in the α-globin gene cluster in a Kabyle population. A combination of singlex and multiplex polymerase chain reaction (PCR)-based assays have been used to identify the molecular defect. Sequencing of the abnormal PCR amplification product revealed a novel α1-globin promoter deletion. The endpoints of the deletion were characterized by sequencing the deletion junctions of the mutated allele. The observed deletion was located 378 bp upstream of the α1-globin gene transcription initiation site and leaves the α2 gene intact. In some patients, the α-α(Δ125) deletion was shown to segregate with Hb S (HBB: c.20A>T) and/or Hb C (HBB: c.19G>A) or a β-thalassemic allele. The α-α(Δ125) deletion has no discernible effect on red cell indices when inherited with no other abnormal globin genes. The family study demonstrated that the deletion is heritable. This is the only example of an intergenic α2-α1 non coding DNA deletion, leaving the α2-globin gene and the α1 coding part intact.

International audience; Multidrug resistance MDR proteins (MRPs) are members of the C family of a group of proteins named ATP binding cassette (ABC) transporters. MRPs can transport drugs including anticancer drugs, nucleoside analogs, antimetabolites and tyrosine kinase inhibitors. Drugs used in HCC therapy, such as tyrosine kinase inhibitor sorafenib, are substrates of uptake and/or efflux transporters. Variable expression of MRPs at the plasma membrane of tumor cells may contribute to drug resistance and subsequent clinical response. Recently, we reported that the hepatocyte SLAMF3 expression (Signaling Lymphocytic Activation Molecule Family member 3) was reduced in tumor cells from hepatocellular carcinoma (HCC) compared to its high expression in adjacent tissues. In the present study, we make a strong correlation between induced SLAMF3 overexpression and the specific loss of MRP-1 expression and its functionalities as a drugs resistance transporter. No changes were observed on expression of ABCG2 and MDR. More importantly, we highlight a strong inverse correlation between MRP-1 and SLAMF3 expression in patients with HCC. We propose that the SLAMF3 overexpression in cancerous cells could represent a potential therapeutic strategy to improve the drugs sensibility of resistant cells and thus control the therapeutic failure in HCC patients.

// Hussein Ghamlouch 1, 2, 5 , Walaa Darwiche 3 , Ahmed Hodroge 1 , Hakim Ouled-Haddou 1 , Sebastien Dupont 1, 5 , Amrathlal Rabbind Singh 1 , Caroline Guignant 1, 2 , Stephanie Trudel 1, 4 , Bruno Royer 1, 5 , Brigitte Gubler 1, 2, 4, * , Jean-Pierre Marolleau 1, 5, * 1 EA4666, LNPC, Universite de Picardie Jules Verne, Amiens, France 2 Department of Immunology, Amiens University Medical Center, Amiens, France 3 PeriTox, Perinatalite & Risques Toxiques, UMR-I 01 Unite mixte INERIS, Amiens, France 4 Department of Molecular Oncobiology, Amiens University Medical Center, Amiens, France 5 Department of Clinical Hematology and Cell Therapy, Amiens University Medical Center, Amiens, France * These authors have contributed equally to this work Correspondence to: Hussein Ghamlouch, e-mail: hussein.ghamlouch@hotmail.com Jean-Pierre Marolleau, e-mail: marolleau.jean-pierre@chu-amiens.fr Keywords: chronic lymphocytic leukemia, B-cell differentiation, apoptosis, LEF1, ROR1 Received: March 10, 2015 Accepted: April 28, 2015 Published: May 11, 2015 ABSTRACT Recent research has shown that chronic lymphocytic leukemia (CLL) B-cells display a strong tendency to differentiate into antibody-secreting cells (ASCs) and thus may be amenable to differentiation therapy. However, the effect of this differentiation on factors associated with CLL pathogenesis has not been reported. In the present study, purified CLL B-cells were stimulated to differentiate into ASCs by phorbol myristate acetate or CpG oligodeoxynucleotide, in combination with CD40 ligand and cytokines in a two-step, seven-day culture system. We investigated (i) changes in the immunophenotypic, molecular, functional, morphological features associated with terminal differentiation into ASCs, (ii) the expression of factors involved in CLL pathogenesis, and (iii) the expression of pro- and anti-apoptotic proteins in the differentiated cells. Our results show that differentiated CLL B-cells are able to display the transcriptional program of ASCs. Differentiation leads to depletion of the malignant program and deregulation of the apoptosis/survival balance. Analysis of apoptosis and the cell cycle showed that differentiation is associated with low cell viability and a low rate of cell cycle entry. Our findings shed new light on the potential for differentiation therapy as a part of treatment strategies for CLL.

Computational analysis of sequence homology of the chiSRC gene cluster, encoding a chitinase in Streptomyces peucetius, showed that the gene cluster could be a two-component regulon comprising a sensor kinase (chiS) and a response regulator (chiR). To prove that the ChiSRC is an authentic two-component system, the chiS gene was cloned and expressed in E.coli and the purified protein was used for biochemical analysis. In this report, we provide biochemical evidence to show that the sensor kinase encoded by chiS gene indeed is a histidine kinase capable of autophosphorylation and the histidine 144 residue of the ChiS protein is the phosphate acceptor. An insertion mutation at the chiS locus led to overproduction chitinase protein in S. peucetius implying that the chiC gene is negatively regulated by the two-component system.