title: The Bin3 RNA methyltransferase targets 7SK RNA to control transcription and translation.
abstract: Bicoid-interacting protein 3 (Bin3) is a conserved RNA methyltransferase found in eukaryotes ranging from fission yeast to humans. It was originally discovered as a Bicoid (Bcd)-interacting protein in Drosophila, where it is required for anterior-posterior and dorso-ventral axis determination in the early embryo. The mammalian ortholog of Bin3 (BCDIN3), also known as methyl phosphate capping enzyme (MePCE), plays a key role in repressing transcription. In transcription, MePCE binds the non-coding 7SK RNA, which forms a scaffold for an RNA-protein complex that inhibits positive-acting transcription elongation factor b, an RNA polymerase II elongation factor. MePCE uses S-adenosyl methionine to transfer a methyl group onto the γ-phosphate of the 5' guanosine of 7SK RNA generating an unusual cap structure that protects 7SK RNA from degradation. Bin3/MePCE also has a role in translation regulation. Initial studies in Drosophila indicate that Bin3 targets 7SK RNA and stabilizes a distinct RNA-protein complex that assembles on the 3'-untranslated region of caudal mRNAs to prevent translation initiation. Much remains to be learned about Bin3/MeCPE function, including how it recognizes 7SK RNA, what other RNA substrates it might target, and how widespread a role it plays in gene regulation and embryonic development.
authors: Department of Biochemistry and Molecular Biology, SUNY-Upstate Medical University, Syracuse, NY, USA.
authors: Michael S
authors: MS
authors: Cosgrove
authors: Ye
authors: Y
authors: Ding
authors: William A
authors: WA
authors: Rennie
authors: Michael J
authors: MJ
authors: Lane
authors: Steven D
authors: SD
authors: Hanes
mesh_terms: D000818:Animals; D017124:Conserved Sequence; D004330:Drosophila; D006801:Humans; D008840:Microfilament Proteins / Q000378:metabolism*; D008954:Models, Biological; D008958:Models, Molecular; D011485:Protein Binding; D014176:Protein Biosynthesis; D017411:Ribonucleoproteins, Small Nuclear / Q000378:metabolism*; D012568:Schizosaccharomyces; D014158:Transcription, Genetic
chemical_list: C430883:BIN3 protein, human; D008840:Microfilament Proteins; D017411:Ribonucleoproteins, Small Nuclear