title: BET Protein BRDT Complexes With HDAC1, PRMT5, and TRIM28 and Functions in Transcriptional Repression During Spermatogenesis.
abstract: The expression of BRDT, a member of the BET sub-family of double bromodomain-containing proteins, is restricted to the male germ line, specifically to pachytene-diplotene spermatocytes and early spermatids. We previously showed that loss of the first bromodomain of BRDT by targeted mutagenesis (Brdt(ΔBD1) ) resulted in sterility and abnormalities in spermiogenesis, but little is known about BRDT's function at the molecular level. As part of studies designed to identify BRDT-interacting proteins we stably introduced a FLAG-tagged BRDT cDNA into 293T cells, which do not normally express BRDT. Affinity-purification of FLAG-tagged BRDT complexes indicated that BRDT has novel interactions with the histone deacetylase HDAC1, the arginine-specific histone methyltransferase 5 PRMT5, and the Tripartite motif-containing 28 protein TRIM28. Immunofluorescent microscopy revealed that BRDT co-localized with each of these proteins in round spermatids and co-immunoprecipitation of testicular extracts showed that these proteins interact with BRDT. Furthermore, they bind the promoter of H1t, a putative target of BRDT-containing complexes. This binding of H1t was lost in mice expressing the Brdt(ΔBD1) mutant protein and concomitantly, H1t expression was elevated in round spermatids. Our study reveals a role for BRDT-containing complexes in the repression of gene expression in vivo that correlates with dramatic effects on chromatin remodeling and the progression of spermiogenesis.
authors.affiliation: Department of Genetics and Development, New York, New York, 10032.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Genetics and Development, New York, New York, 10032.|Department of Obstetrics and Gynecology, New York, New York, 10032.|Institute of Human Nutrition, New York, New York, 10032.|Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, New York, 10032.
authors.forename: Debra J
authors.initials: DJ
authors.lastname: Wolgemuth
mesh_terms: D000818:Animals; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D056284:Histone Deacetylase 1 / Q000378:metabolism*; D006801:Humans; D008297:Male; D051379:Mice; D046912:Multiprotein Complexes / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011484:Protein-Arginine N-Methyltransferases / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism*; D013087:Spermatids / Q000378:metabolism; D013091:Spermatogenesis; D014158:Transcription, Genetic; D000092468:Bromodomain Containing Proteins
chemical_list: D056284:Histone Deacetylase 1; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D011484:Protein-Arginine N-Methyltransferases; D012097:Repressor Proteins; C109570:BRDT protein, human; D000092468:Bromodomain Containing Proteins; C518475:BRDT protein, mouse
keywords: BRDT; SPERMATOGENESIS; TRANSCRIPTIONAL REPRESSION