Sm and Sm-like proteins belong to a large family: identification of proteins of the U6 as well as the U1, U2, U4 and U5 snRNPs.
AUTOR(ES)
Séraphin, B
RESUMO
Several small nuclear RNAs (snRNAs), including the spliceosomal U1, U2, U4 and U5 snRNAs, are associated with Sm proteins. These eight small proteins form a heteromeric complex that binds to snRNAs and plays a major role in small nuclear ribonucleoprotein (snRNP) biogenesis and transport. These proteins are also a major target for autoantibodies in the human disease systemic lupus erythematosus. By sequence comparison I have shown that all the known Sm proteins share a common structural motif which might explain their immunological cross-reactivity. Database searches using this motif uncovered a large number of Sm-like proteins from plants, animals and fungi. These proteins have been grouped in at least 13 different subfamilies. Genes encoding divergent yeast members were cloned and used to produce tagged fusion proteins. Some of these proteins are canonical Sm proteins as they associate with the yeast U1, U2, U4/U6 and U5 snRNAs. Surprisingly, one Sm-like protein was found to be a component of the U6 snRNP. These findings have implications for the structure of the Sm protein complex, spliceosomal snRNP evolution, snRNA transport and modification as well as the involvement of Sm proteins in systemic lupus erythematosus.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=398309Documentos Relacionados
- Pre-mRNA splicing by complementation with purified human U1, U2, U4/U6 and U5 snRNPs.
- Purification of snRNPs U1, U2, U4, U5 and U6 with 2,2,7-trimethylguanosine-specific antibody and definition of their constituent proteins reacting with anti-Sm and anti-(U1)RNP antisera.
- In vitro reconstitution of mammalian U2 and U5 snRNPs active in splicing: Sm proteins are functionally interchangeable and are essential for the formation of functional U2 and U5 snRNPs.
- Identification of an RNA-dependent ATPase activity in mammalian U5 snRNPs.
- Evidence for three distinct D proteins, which react differentially with anti-Sm autoantibodies, in the cores of the major snRNPs U1, U2, U4/U6 and U5.
