title: A growth-essential Tetrahymena Piwi protein carries tRNA fragment cargo.
abstract: Argonaute/Piwi proteins associate with small RNAs that typically provide sequence specificity for RNP function in gene and genome regulation. Here we show that Twi12, a Tetrahymena Piwi protein essential for growth, is loaded with mature tRNA fragments. The tightly bound ~18- to 22-nucleotide tRNA 3' fragments are biochemically distinct from the tRNA halves produced transiently in response to stress. Notably, the end positions of Twi12-bound tRNA 3' fragments precisely match RNAs detected in total small RNA of mouse embryonic stem cells and human cancer cells. Our studies demonstrate unanticipated evolutionary conservation of mature tRNA processing to tRNA fragment small RNAs.
authors.affiliation: Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California 94720, USA.
authors.forename: Mary T
authors.initials: MT
authors.lastname: Couvillion
authors.forename: Ravi
authors.initials: R
authors.lastname: Sachidanandam
authors.forename: Kathleen
authors.initials: K
authors.lastname: Collins
mesh_terms: D001483:Base Sequence; D005075:Biological Evolution; D015800:Protozoan Proteins / Q000378:metabolism* / Q000502:physiology; D012323:RNA Processing, Post-Transcriptional; D012343:RNA, Transfer / Q000378:metabolism*; D013768:Tetrahymena / Q000235:genetics* / Q000254:growth & development
chemical_list: D015800:Protozoan Proteins; D012343:RNA, Transfer