Unique Sm core structure of U7 snRNPs: assembly by a specialized SMN complex and the role of a new component, Lsm11, in histone RNA processing.

ABSTRACT: A set of seven Sm proteins assemble on the Sm-binding site of spliceosomal U snRNAs to form the ring-shaped Sm core. The U7 snRNP involved in histone RNA 3' processing contains a structurally similar but biochemically unique Sm core in which two of these proteins, Sm D1 and D2, are replaced by Lsm10 and by another as yet unknown component. Here we characterize this factor, termed Lsm11, as a novel Sm-like protein with apparently two distinct functions. In vitro studies suggest that its long N-terminal part mediates an important step in histone mRNA 3'-end cleavage, most likely by recruiting a zinc finger protein previously identified as a processing factor. In contrast, the C-terminal part, which comprises two Sm motifs interrupted by an unusually long spacer, is sufficient to assemble wit

SUBMITTER: Pillai RS 

PROVIDER: S-EPMC196468 | biostudies-literature | 2003 Sep

REPOSITORIES: biostudies-literature