scholarly journals The zinc finger protein CLAMP promotes long-range chromatin interactions that mediate dosage compensation of the Drosophila male X-chromosome

2020 ◽  
Author(s):  
William Jordan ◽  
Erica Larschan

SummaryDrosophila dosage compensation is an important model system for defining how active chromatin domains are formed. The Male-specific lethal dosage compensation complex (MSLc) increases transcript levels of genes along the length of the single male X-chromosome to equalize with that on the two female X-chromosomes. The strongest binding sites for MSLc cluster together in three-dimensional space independent of MSLc because clustering occurs in both sexes. CLAMP, a non-sex specific, ubiquitous zinc finger protein, binds synergistically with MSLc to enrich the occupancy of both factors on the male X-chromosome. Here, we demonstrate that CLAMP promotes the observed clustering of MSLc bindings sites. Genome-wide, CLAMP promotes interactions between active chromatin regions. Moreover, the X-enriched CLAMP protein more strongly promotes longer-range interactions on the X-chromosome than autosomes. Genome-wide, CLAMP promotes interactions between active chromatin regions together with other insulator proteins. Overall, we define how long-range interactions which are modulated by a locally enriched ubiquitous transcription factor promote hyper-activation of the X-chromosome to mediate dosage compensation.

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
William Jordan ◽  
Erica Larschan

Abstract Background Drosophila dosage compensation is an important model system for defining how active chromatin domains are formed. The male-specific lethal dosage compensation complex (MSLc) increases transcript levels of genes along the length of the single male X-chromosome to equalize with that expressed from the two female X-chromosomes. The strongest binding sites for MSLc cluster together in three-dimensional space largely independent of MSLc because clustering occurs in both sexes. CLAMP, a non-sex specific, ubiquitous zinc finger protein, binds synergistically with MSLc to enrich the occupancy of both factors on the male X-chromosome. Results Here, we demonstrate that CLAMP promotes the observed three-dimensional clustering of MSLc binding sites. Moreover, the X-enriched CLAMP protein more strongly promotes longer-range three-dimensional interactions on the X-chromosome than autosomes. Genome-wide, CLAMP promotes three-dimensional interactions between active chromatin regions together with other insulator proteins. Conclusion Overall, we define how long-range interactions which are modulated by a locally enriched ubiquitous transcription factor promote hyper-activation of the X-chromosome to mediate dosage compensation.


2007 ◽  
Vol 27 (24) ◽  
pp. 8760-8769 ◽  
Author(s):  
Kathleen A. Worringer ◽  
Barbara Panning

ABSTRACT In organisms with sex chromosomes, dosage compensation equalizes gene expression between the sexes. In Drosophila melanogaster males, the male-specific lethal (MSL) complex of proteins and two noncoding roX RNAs coat the X chromosome, resulting in a twofold transcriptional upregulation to equalize gene expression with that of females. How MSL complex enrichment on the X chromosome is regulated is not well understood. We performed an RNA interference screen to identify new factors required for dosage compensation. Using a Drosophila Schneider S2 cell line in which green fluorescent protein (GFP)-tagged MSL2 localizes to the X chromosome, we assayed ∼7,200 knockdowns for their effects on GFP-MSL2 distribution. One factor identified is the zinc finger protein Zn72D. In its absence, the MSL complex no longer coats the X chromosome. We demonstrate that Zn72D is required for productive splicing of the transcript for the MSL protein Maleless, explaining the dosage compensation defect. However, Zn72D is required for the viability of both sexes, indicating its functions are not sex specific. Consistent with this, Zn72D colocalizes with elongating RNA polymerase II, implicating it as a more general factor involved in RNA metabolism.


2016 ◽  
Author(s):  
Jennifer A. Urban ◽  
Caroline A. Doherty ◽  
William T. Jordan ◽  
Jacob E. Bliss ◽  
Jessica Feng ◽  
...  

AbstractDosage compensation is a fundamental mechanism in many species that corrects for the inherent imbalance in X-chromosome copy number between XY males and XX females. In Drosophila melanogaster, transcriptional output from the single male X-chromosome is equalized to that of XX females by recruitment of the Male Specific Lethal (MSL) complex to specific sequences along the length of the X-chromosome. The initial recruitment of MSL complex to the X-chromosome is dependent on a recently discovered zinc finger protein called Chromatin-Linked Adapter for MSL Proteins (CLAMP). However, further studies on the in vivo function of CLAMP remained difficult because the location of the gene in pericentric heterochromatin made it challenging to create null mutations or deficiencies. Using the CRISPR/Cas9 genome editing system, we generated the first null mutant in the clamp gene that eliminates expression of CLAMP protein. We show that CLAMP is necessary for both male and female viability. While females die at the third instar larval stage, males die earlier, likely due to the essential role of CLAMP in male dosage compensation. Moreover, we demonstrate that CLAMP promotes dosage compensation in males and represses key male-specific transcripts involved in sex-determination in females. Our results reveal that CLAMP is an essential protein with dual roles in males and females, which together assure that dosage compensation is a sex-specific process.


2007 ◽  
Vol 85 (3) ◽  
pp. 358-365 ◽  
Author(s):  
Annalisa Onori ◽  
Agata Desantis ◽  
Serena Buontempo ◽  
Maria Grazia Di Certo ◽  
Maurizio Fanciulli ◽  
...  

Our aim is to upregulate the expression of the dystrophin-related gene utrophin in Duchenne muscular dystrophy, in this way complementing the lack of dystrophin function. To achieve utrophin upregulation, we designed and engineered synthetic zinc-inger based transcription factors. We have previously shown that the artificial 3-zinc-finger protein Jazz, fused with the appropriate effector domain, is able to drive the transcription of a test gene from utrophin promoter A. Here we report a novel artificial 4-zinc-finger protein, Bagly, which binds with optimized affinity–specificity to a 12 bp DNA target sequence that is internal to human utrophin promoter A. Bagly was generated adding to Jazz protein an extra-fourth zinc finger, derived from transcription factor YY1. Importantly, the Bagly DNA target sequence is statistically present in the human genome only 210 times, about 60 fewer times than the 9 bp Jazz DNA target sequence. Thanks to its additional zinc-finger domain, Bagly protein shows enhanced transcriptional activity. Moreover, we demonstrated Bagly's effective access and binding to active chromatin in the chromosomal context and its ability to upregulate endogenous utrophin.


Science ◽  
1995 ◽  
Vol 268 (5212) ◽  
pp. 886-889 ◽  
Author(s):  
R Bruschweiler ◽  
X Liao ◽  
P. Wright

2020 ◽  
Vol 21 (16) ◽  
pp. 5762
Author(s):  
Andrea Balogh ◽  
Lilla Reiniger ◽  
Szabolcs Hetey ◽  
Peter Kiraly ◽  
Eszter Toth ◽  
...  

Zinc finger protein 554 (ZNF554), a member of the Krüppel-associated box domain zinc finger protein subfamily, is predominantly expressed in the brain and placenta in humans. Recently, we unveiled that ZNF554 regulates trophoblast invasion during placentation and its decreased expression leads to the early pathogenesis of preeclampsia. Since ZNF proteins are immensely implicated in the development of several tumors including malignant tumors of the brain, here we explored the pathological role of ZNF554 in gliomas. We examined the expression of ZNF554 at mRNA and protein levels in normal brain and gliomas, and then we searched for genome-wide transcriptomic changes in U87 glioblastoma cells transiently overexpressing ZNF554. Immunohistochemistry of brain tissues in our cohort (n = 62) and analysis of large TCGA RNA-Seq data (n = 687) of control, oligodendroglioma, and astrocytoma tissues both revealed decreased expression of ZNF554 towards higher glioma grades. Furthermore, low ZNF554 expression was associated with shorter survival of grade III and IV astrocytoma patients. Overexpression of ZNF554 in U87 cells resulted in differential expression, mostly downregulation of 899 genes. The “PI3K-Akt signaling pathway”, known to be activated during glioma development, was the most impacted among 116 dysregulated pathways. Most affected pathways were cancer-related and/or immune-related. Congruently, cell proliferation was decreased and cell cycle was arrested in ZNF554-transfected glioma cells. These data collectively suggest that ZNF554 is a potential tumor suppressor and its decreased expression may lead to the loss of oncogene suppression, activation of tumor pathways, and shorter survival of patients with malignant glioma.


2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Abeer Fadda ◽  
Najeeb Syed ◽  
Rafah Mackeh ◽  
Anna Papadopoulou ◽  
Shigeru Suzuki ◽  
...  

2001 ◽  
Vol 183 (23) ◽  
pp. 6917-6923 ◽  
Author(s):  
Wenjie Xu ◽  
Aaron P. Mitchell

ABSTRACT The Saccharomyces cerevisiae zinc finger protein Rim101p is activated by cleavage of its C-terminal region, which resembles PEST regions that confer susceptibility to proteolysis. Here we report that Rim20p, a member of the broadly conserved PalA/AIP1/Alix family, is required for Rim101p cleavage. Two-hybrid and coimmunoprecipitation assays indicate that Rim20p binds to Rim101p, and a two-hybrid assay shows that the Rim101p PEST-like region is sufficient for Rim20p binding. Rim101p-Rim20p interaction is conserved in Candida albicans, supporting the idea that interaction is functionally significant. Analysis of Rim20p mutant proteins indicates that some of its broadly conserved regions are required for processing of Rim101p and for stability of Rim20p itself but are not required for interaction with Rim101p. A recent genome-wide two-hybrid study (T. Ito, T. Chiba, R. Ozawa, M. Yoshida, M. Hattori, and Y. Sakaki, Proc. Natl. Acad. Sci. USA 98:4569–4574, 2000) indicates that Rim20p interacts with Snf7p and that Snf7p interacts with Rim13p, a cysteine protease required for Rim101p proteolysis. We suggest that Rim20p may serve as part of a scaffold that places Rim101p and Rim13p in close proximity.


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