Project description:We investigate the role of Snf2l in ovaries by characterizing a mouse bearing an inactivating deletion on the ATPase domain of Snf2l (Ex6DEL). Snf2l mutant mice produce significantly fewer eggs than control mice when superovulated. Thus, gonadotropin stimulation leads to a significant deficit in secondary follicles and an increase in abnormal antral follicles. We profiled the expression of granulosa cells from Snf2l WT and Ex6DEL mice treated with pregnant mares' serum gonadotropin followed by human chorionic gonadotropin Granulosa cells from either Snf2l WT or Ex6DEL mice treated with PMSG followed by hCG were collected at 0h and 4h post-hCG. Each array includes granulosa cells pooled from 5 mice.
Project description:ISWI is an evolutionary conserved ATPase that catalyzes nucleosome remodeling in several different complexes. Two mammalian ISWI orthologs, SNF2H and SNF2L, have specialized functions despite their high similarity. Due to the lack of reagents the functions of SN2L in human cells had not been established. Newly established specific monoclonal antibodies and selective RNA interference protocols now enabled a comprehensive characterization of loss-of-function phenotypes in human cells. Contrasting earlier results obtained in the mouse model, we found SNF2L broadly expressed in primary human tissues. Depletion of SNF2L in HeLa cells led to enhanced proliferation, morphological alterations and increased migration. These phenomena were explained by transcriptome profiling, which identified SNF2L as a modulator of the Wnt signaling network. The cumulative effects of SNF2L depletion on gene expression portray the cell in a state of activated Wnt signaling characterized by increased proliferation and chemotactic locomotion. High levels of SNF2L expression in normal melanocytes contrast to undetectable expression in malignant melanoma. In summary, our data document an anti-correlation between SNF2L expression and several features characteristic of malignant cells. Total RNA samples from human HeLa cells. Transcript levels were analyzed after luciferase, SNF2H and SNF2L RNAi.
Project description:We investigate the role of Snf2l in ovaries by characterizing a mouse bearing an inactivating deletion on the ATPase domain of Snf2l (Ex6DEL). Snf2l mutant mice produce significantly fewer eggs than control mice when superovulated. Thus, gonadotropin stimulation leads to a significant deficit in secondary follicles and an increase in abnormal antral follicles. We profiled the expression of granulosa cells from Snf2l WT and Ex6DEL mice treated with pregnant mares' serum gonadotropin followed by human chorionic gonadotropin
Project description:ISWI is an evolutionary conserved ATPase that catalyzes nucleosome remodeling in several different complexes. Two mammalian ISWI orthologs, SNF2H and SNF2L, have specialized functions despite their high similarity. Due to the lack of reagents the functions of SN2L in human cells had not been established. Newly established specific monoclonal antibodies and selective RNA interference protocols now enabled a comprehensive characterization of loss-of-function phenotypes in human cells. Contrasting earlier results obtained in the mouse model, we found SNF2L broadly expressed in primary human tissues. Depletion of SNF2L in HeLa cells led to enhanced proliferation, morphological alterations and increased migration. These phenomena were explained by transcriptome profiling, which identified SNF2L as a modulator of the Wnt signaling network. The cumulative effects of SNF2L depletion on gene expression portray the cell in a state of activated Wnt signaling characterized by increased proliferation and chemotactic locomotion. High levels of SNF2L expression in normal melanocytes contrast to undetectable expression in malignant melanoma. In summary, our data document an anti-correlation between SNF2L expression and several features characteristic of malignant cells.
Project description:ISWI-family nucleosome remodeling enzymes need the histone H4 N-terminal tail to mobilize nucleosomes. Here we mapped the H4-tail binding pocket of ISWI. Surprisingly the binding site was adjacent to but not overlapping with the docking site of an auto-regulatory motif, AutoN, in the N-terminal region (NTR) of ISWI, indicating that AutoN does not act as a simple pseudosubstrate as suggested previously. Rather, AutoN cooperated with a hitherto uncharacterized motif, termed AcidicN, to confer H4-tail sensitivity and discriminate between DNA and nucleosomes. A third motif in the NTR, ppHSA, was functionally required in vivo and provided structural stability by clamping the NTR to Lobe 2 of the ATPase domain. This configuration is reminiscent of Chd1 even though Chd1 contains an unrelated NTR. Our results shed light on the intricate structural and functional regulation of ISWI by the NTR and uncover surprising parallels with Chd1. Elife. 2017 Jan 21;6. pii: e21477. doi: 10.7554/eLife.21477. [Epub ahead of print]
Project description:Sleep disruptions are among the most commonly-reported symptoms across neurodevelopmental disorders (NDDs), but mechanisms linking brain development to normal sleep are largely unknown. From a Drosophila screen of human NDD-associated risk genes, we identified the chromatin remodeler Imitation SWItch/SNF (ISWI) to be required for adult fly sleep. To better understand the mechanisms by which ISWI regulates sleep, we performed RNA-Seq analysis on mid-3rd instar larval central nervous systems (central brain + ventral nerve cord) in the setting of pan-neuronal ISWI knockdown (elav-GAL4>UAS-ISWI RNAi) compared to controls (elav-GAL4;+). We chose mid-3rd instar because temporal mapping revealed ISWI knockdown during this pre-adult developmental stage led to adult fly sleep deficits.
Project description:Profiling of changes in steady state RNA levels upon RNAi-mediated knockdown of the nucleosome remodeling ATPase ISWI in Drosophila SL2 cells. Quantitation of the corresponding proteomes has been performed to describe transcriptome-proteome relations. The analysis indicates a limited correlation of the two expression steps. Experiment Overall Design: Drosophila SL2 cells were incubated 7 days after treatment with 10 ug of dsRNA directed against GST or ISWI, respectively. 3 biological replicates per experimental conditions have been collected.
Project description:Chromatin remodeling is a general mechanism involved in DNA-dependent processes, including gene expression regulation. ISWI ATPase is the catalytic subunit in diverse chromatin remodeling complexes that changing histone–DNA interactions and therefore play a pivotal role in different nuclear processes. Here, the ISWI remodeler was fused to GFP (NH and CO fusions) and its partners were determined by affinity purification-mass spectrometry (MS) assay. This approach identified known ISWI partners (NLP, RCCP and FYRP), previously characterized in T. brucei, and new components of TcISWI complex (DRBD2, DHH1 and proteins containing SMC domains).
Project description:Remodelers define nucleosome composition, presence and position. Mammalian imitation-switch-type (ISWI) comprise one class, mostly relying on the ATPase Snf2h for activity. We show that embryonic stem cells are viable without Snf2h, enabling to study its function and contrast it to Brg1, the ATPase of SWI/SNF. Loss of Snf2h specifically affects nucleosomal positioning and increases linker lengths genome-wide providing in vivo evidence for ISWI function in ruling nucleosomal spacing. Systematic analysis of transcription factor binding reveals selective requirement on either remodeling activity. One group, containing the transcriptional repressor REST depend on BRG1, while a non-overlapping set including the insulator protein CTCF, relies on Snf2h. Importantly localized reduction in CTCF binding decreases long-range interactions. Collectively, this links mammalian ISWI to nuclear organization, demonstrates its cellular role for nucleosomal periodicity and reveals that transcription factors rely on specific remodeling pathways for proper genomic binding.