8q66
Crystal Structure of the C. elegans MUT-7 MUT-8 CTD complex
Structural highlights
FunctionMUT7_CAEEL Represses the transposition of Tc1, Tc3, Tc4, and Tc5, perhaps by degrading transposon-specific messages. Also affects sperm development, sensitivity to RNAi of mainly germline expressed genes, silencing of some germline transgenes, X chromosome loss, and is required for cosuppression (functional silencing of chromosomal loci induced by transgenes) and for silencing induced by antisense RNA oligomers.[1] Publication Abstract from PubMedThe MUT-7 family of 3'-5' exoribonucleases is evolutionarily conserved across the animal kingdom and plays essential roles in small RNA production in the germline. Most MUT-7 homologues carry a C-terminal domain of unknown function named MUT7-C appended to the exoribonuclease domain. Our analysis shows that the MUT7-C is evolutionary ancient, as a minimal version of the domain exists as an individual protein in prokaryotes. In animals, MUT7-C has acquired an insertion that diverged during evolution, expanding its functions. Caenorhabditis elegans MUT-7 contains a specific insertion within MUT7-C, which allows binding to MUT-8 and, consequently, MUT-7 recruitment to germ granules. In addition, in C. elegans and human MUT-7, the MUT7-C domain contributes to RNA binding and is thereby crucial for ribonuclease activity. This RNA-binding function most likely represents the ancestral function of the MUT7-C domain. Overall, this study sheds light on MUT7-C and assigns two functions to this previously uncharacterized domain. MUT-7 exoribonuclease activity and localization are mediated by an ancient domain.,Busetto V, Pshanichnaya L, Lichtenberger R, Hann S, Ketting RF, Falk S Nucleic Acids Res. 2024 Aug 27;52(15):9076-9091. doi: 10.1093/nar/gkae610. PMID:39188014[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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