A multiprotein complex mediates the ATP-dependent assembly of spliceosomal U snRNPs.

摘要: The spliceosomal snRNPs U1, U2, U4 and U5 contain a common RNP structure termed the Sm core that is formed by binding of proteins onto U snRNA. Although isolated assemble spontaneously snRNAs in vitro, there increasing evidence SMN its interactor Gemin2 are involved this process vivo. Here, we describe cell-free assay system for assembly closely reproduces vivo conditions. Using system, show U1 snRNP depends on ATP. Immunodepletion SMN–Gemin2 from extract abolished even though contained high levels proteins. An affinity-purified macromolecular complex consisting 16 components including all restored immunodepleted extract. These data provide first direct containing mediates active snRNPs.