Send to

Choose Destination
RNA. 1997 Dec;3(12):1374-87.

A new cyclophilin and the human homologues of yeast Prp3 and Prp4 form a complex associated with U4/U6 snRNPs.

Author information

Cold Spring Harbor Laboratory, New York 11724, USA.


We have purified three new human U4/U6-snRNP proteins from HeLa cells. The three proteins formed a tightly bound complex and behaved as a single species throughout the purification. All three proteins have been identified by peptide sequencing, and full-length cDNA sequences have been obtained for all of them. Two of the proteins are homologues of the Saccharomyces cerevisiae splicing factors Prp3 and Prp4, and the third protein is a cyclophilin. Both the human and S. cerevisiae Prp4 proteins have seven repeats of the WD motif and likely fold into structures very similar to those of the beta subunits of G proteins. The human Prp3 protein is highly basic and is closely related to S. cerevisiae Prp3 only in its carboxyl-terminal half. The human homologues of Prp3 and Prp4 are part of a stable complex in the absence of RNA. The third protein in the complex is a new cyclophilin. Cyclophilins have been proposed to act as chaperones in a variety of cellular processes, and we discuss some possible roles of this U4/U6 snRNP-associated cyclophilin.

[Indexed for MEDLINE]
Free PMC Article

Publication types, MeSH terms, Substances, Secondary source ID, Grant support

Publication types

MeSH terms


Secondary source ID

Grant support

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center