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p110, a novel human U6 snRNP protein and U4/U6 snRNP recycling factor
Author(s) -
Bell Mathias,
Schreiner Silke,
Damianov Andrey,
Reddy Ram,
Bindereif Albrecht
Publication year - 2002
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/21.11.2724
Subject(s) - snrnp , biology , microbiology and biotechnology , genetics , ribonucleoprotein , rna , gene
During each spliceosome cycle, the U6 snRNA undergoes extensive structural rearrangements, alternating between singular, U4–U6 and U6–U2 base‐paired forms. In Saccharomyces cerevisiae , Prp24 functions as an snRNP recycling factor, reannealing U4 and U6 snRNAs. By database searching, we have identified a Prp24‐related human protein previously described as p110 nrb or SART3. p110 contains in its C‐terminal region two RNA recognition motifs (RRMs). The N‐terminal two‐thirds of p110, for which there is no counterpart in the S.cerevisiae Prp24, carries seven tetratricopeptide repeat (TPR) domains. p110 homologs sharing the same domain structure also exist in several other eukaryotes. p110 is associated with the mammalian U6 and U4/U6 snRNPs, but not with U4/U5/U6 tri‐snRNPs nor with spliceosomes. Recombinant p110 binds in vitro specifically to human U6 snRNA, requiring an internal U6 region. Using an in vitro recycling assay, we demonstrate that p110 functions in the reassembly of the U4/U6 snRNP. In summary, p110 represents the human ortholog of Prp24, and associates only transiently with U6 and U4/U6 snRNPs during the recycling phase of the spliceosome cycle.