Genome-wide analysis of dMi-2 binding sites

ATP-dependent chromatin remodelers regulate gene expression. The actions of chromatin remodelers on the nucleosome removal and assembly, the histone variants exchange and the modifications of the nucleosome array modify the accessibility of the transcriptional machinery to DNA. Transcription is also influenced by the chromatin context. Indeed, the presence of transcription factors, nucleosome-depleted regions and histone modifications, facilitate the recruitment of specific histone modifying enzymes, chromatin modifying enzymes and chromatin remodelers. Thus, several chromatin features influence the transcription outcome. The ATP-dependent chromatin remodeler dMi-2 is typically associated with transcription repression, but its implication in active transcription has also been reported. The dMi-2 binding sites on polytene chromosomes suggest that dMi-2 binds mainly in open chromatin regions. However, the resolution of polytene staining is approximate and does not give any information about the chromatin context surrounding dMi-2. Thus, the genome-wide dMi-2 binding sites have been identified by ChIP-sequencing and correlated with existing data of histone modifications, RNA polymerase II, nucleosome-depleted regions, transcription, transcription factors and chromatin states. All in all, dMi-2 is located in open chromatin regions and in vicinity of developmental genes. Although dMi-2 mainly represses the expression of its associated genes, it binds close to features linked to active transcription and it is enriched in promoters and in potential regulatory regions. Upon heat shock, the inducible hsp70 gene is actively transcribed, and dMi-2 is important for its expression. To investigate the factors influencing the recruitment of dMi-2 in a context of active transcription, the dMi-2 genome-wide binding sites in un-induced and heat shock conditions have been identified by ChIP-sequencing. dMi-2 is selectively enriched on 7 hsp genes. The chromatin features associated to the hsp70 promoter or a nucleosome-depleted region does not suffice to recruit dMi-2. Moreover, a strong transcription is not sufficient to recruit dMi-2, even though its recruitment on the heat shock genes is transcription dependent. Notably, dMi-2 distribution encompasses the gene body and extent beyond the polyadenylation site of the heat shock genes. Thus, the results suggest that dMi-2 follow the transcriptional activity

Identification des TRPC exprimés dans les cellules glomérulées bovines et les cardiomyocytes de rat et localisation cellulaire de TRPC6

L'étude de la phototransduction chez la drosophile a amené l'identification de canaux calciques membranaires exprimés chez les mammifères nommés TRPC. Leurs modes d'activation dépendent de la concentration luminale de calcium dans le réticulum endoplasmique et/ou de l'activation d'un récepteur couplé à une protéine Gq. Par contre, leurs mécanismes d'activation et leurs rôles physiologiques restent incertains. Une première partie de ce mémoire porte sur l'identification des TRPC exprimés dans les cellules glomérulées bovines et dans les cardiomyocytes de rat par RT-PCR. Chez les cardiomyocytes de rat, nos résultats démontrent une expression des TRPC1, TRPC3, TRPC4 et TRPC7. Dans la seconde partie de ce mémoire, nous avons procédé à une caractérisation de l'anticorps anti-TRPC6 pour des études d'immunofluorescence avec des cellules HEK 293 exprimant de façon stable mTRPC6 ou avec des cellules COS.7 transfectées de façon transitoire avec mTRPC6."--Résumé abrégé par UMI

Recruitment of the ATP-dependent chromatin remodeler dMi-2 to the transcribed region of active heat shock genes

The ATP-dependent chromatin remodeler dMi-2 can play both positive and negative roles in gene transcription. Recently, we have shown that dMi-2 is recruited to the hsp70 gene in a heat shock-dependent manner, and is required to achieve high transcript levels. Here, we use chromatin immunoprecipitation sequencing (ChIP-Seq) to identify other chromatin regions displaying increased dMi-2 binding upon heat shock and to characterize the distribution of dMi-2 over heat shock genes. We show that dMi-2 is recruited to the body of at least seven heat shock genes. Interestingly, dMi-2 binding extends several hundred base pairs beyond the polyadenylation site into the region where transcriptional termination occurs. We find that dMi-2 does not associate with the entire nucleosome-depleted hsp70 locus 87A. Rather, dMi-2 binding is restricted to transcribed regions. Our results suggest that dMi-2 distribution over active heat shock genes are determined by transcriptional activity

LINT, a Novel dL(3)mbt-Containing Complex, Represses Malignant Brain Tumour Signature Genes

Mutations in the l(3)mbt tumour suppressor result in overproliferation of Drosophila larval brains. Recently, the derepression of different gene classes in l(3)mbt mutants was shown to be causal for transformation. However, the molecular mechanisms of dL(3)mbt-mediated gene repression are not understood. Here, we identify LINT, the major dL(3)mbt complex of Drosophila. LINT has three core subunits—dL(3)mbt, dCoREST, and dLint-1—and is expressed in cell lines, embryos, and larval brain. Using genome-wide ChIP–Seq analysis, we show that dLint-1 binds close to the TSS of tumour-relevant target genes. Depletion of the LINT core subunits results in derepression of these genes. By contrast, histone deacetylase, histone methylase, and histone demethylase activities are not required to maintain repression. Our results support a direct role of LINT in the repression of brain tumour-relevant target genes by restricting promoter access

Identification des TRPC exprimés dans les cellules glomérulées bovines et les cardiomyocytes de rat et localisation cellulaire de TRPC6

L'étude de la phototransduction chez la drosophile a amené l'identification de canaux calciques membranaires exprimés chez les mammifères nommés TRPC. Leurs modes d'activation dépendent de la concentration luminale de calcium dans le réticulum endoplasmique et/ou de l'activation d'un récepteur couplé à une protéine Gq. Par contre, leurs mécanismes d'activation et leurs rôles physiologiques restent incertains. Une première partie de ce mémoire porte sur l'identification des TRPC exprimés dans les cellules glomérulées bovines et dans les cardiomyocytes de rat par RT-PCR. Chez les cardiomyocytes de rat, nos résultats démontrent une expression des TRPC1, TRPC3, TRPC4 et TRPC7. Dans la seconde partie de ce mémoire, nous avons procédé à une caractérisation de l'anticorps anti-TRPC6 pour des études d'immunofluorescence avec des cellules HEK 293 exprimant de façon stable mTRPC6 ou avec des cellules COS.7 transfectées de façon transitoire avec mTRPC6."--Résumé abrégé par UMI

Genome-wide analysis of dMi-2 binding sites

ATP-dependent chromatin remodelers regulate gene expression. The actions of chromatin remodelers on the nucleosome removal and assembly, the histone variants exchange and the modifications of the nucleosome array modify the accessibility of the transcriptional machinery to DNA. Transcription is also influenced by the chromatin context. Indeed, the presence of transcription factors, nucleosome-depleted regions and histone modifications, facilitate the recruitment of specific histone modifying enzymes, chromatin modifying enzymes and chromatin remodelers. Thus, several chromatin features influence the transcription outcome. The ATP-dependent chromatin remodeler dMi-2 is typically associated with transcription repression, but its implication in active transcription has also been reported. The dMi-2 binding sites on polytene chromosomes suggest that dMi-2 binds mainly in open chromatin regions. However, the resolution of polytene staining is approximate and does not give any information about the chromatin context surrounding dMi-2. Thus, the genome-wide dMi-2 binding sites have been identified by ChIP-sequencing and correlated with existing data of histone modifications, RNA polymerase II, nucleosome-depleted regions, transcription, transcription factors and chromatin states. All in all, dMi-2 is located in open chromatin regions and in vicinity of developmental genes. Although dMi-2 mainly represses the expression of its associated genes, it binds close to features linked to active transcription and it is enriched in promoters and in potential regulatory regions. Upon heat shock, the inducible hsp70 gene is actively transcribed, and dMi-2 is important for its expression. To investigate the factors influencing the recruitment of dMi-2 in a context of active transcription, the dMi-2 genome-wide binding sites in un-induced and heat shock conditions have been identified by ChIP-sequencing. dMi-2 is selectively enriched on 7 hsp genes. The chromatin features associated to the hsp70 promoter or a nucleosome-depleted region does not suffice to recruit dMi-2. Moreover, a strong transcription is not sufficient to recruit dMi-2, even though its recruitment on the heat shock genes is transcription dependent. Notably, dMi-2 distribution encompasses the gene body and extent beyond the polyadenylation site of the heat shock genes. Thus, the results suggest that dMi-2 follow the transcriptional activity

Supplementary Material for: Hybrid Method for Peritoneal Dialysis Catheter Insertion: A New Technique for Improved Outcomes and Reduced Costs

Background: Peritoneal Dialysis (PD) is a well-established treatment choice for end-stage kidney disease (ESKD). While there are several methods for PD catheter insertion, they each have limitations. In this study, we present a new hybrid method for PD catheter insertion and compare it to the conventional laparoscopic method. Methods: This retrospective study included 171 patients who were undergoing their first PD catheter insertion, and a total of 20% of the enrolled patients had a past medical history of abdominal surgery. Out of these, 101 patients underwent the laparoscopic method and 70 underwent a new invented hybrid method. The study aimed to compare the surgical outcomes, incidence of early and late complications, hospital stay, and medical expenses between the two groups. Results: There were no notable differences in basic demographic features and comorbid conditions between the two groups. The results of our data revealed that the hybrid group had a significantly shorter break-in period and did not require temporary hemodialysis. Additionally, length of hospital stay and medical costs were significantly lower in the hybrid group. (all p<0.05) The incidence of early complications was lower in the hybrid group, while the incidence of late complications was comparable between the two groups. Conclusion: Our study demonstrates that the hybrid method of PD catheter insertion provides a safe and efficient alternative to the traditional laparoscopic method, enabling urgent-start PD and reducing hospital stays and medical expenses. Our findings support the use of the hybrid method as a new standard of care for ESKD patients undergoing PD catheter insertion