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Functional redundancy of worm spliceosomal proteins U1A and U2B
Functional redundancy of worm spliceosomal proteins U1A and U2B''.
89
In Caenorhabditis elegans, the small nuclear ribonucleoprotein (snRNP)-associated proteins U1A and U2B'' are approximately 50% identical to each other, and neither bears signature characteristics of mammalian U1A or U2B'' or the single Drosophila homolog, SNF. We show here that the genes that encode these proteins (rnp-2 and rnp-3) are cotranscribed in an operon, and that ribonucleoprotein RNP-2 is U1 snRNP-associated (U1A) whereas RNP-3 is U2 snRNP-associated (U2B''). U2B'' interacts with U2 even in the absence of another U2 snRNP protein, U2A'. Like U1A and U2B'' from yeast, plants, and vertebrates, worm U1A and U2B'' are more similar to each other than they are to other U1A or U2B'' proteins, respectively. Even though U1A and U2B'' interact with different snRNPs, they are functionally redundant; knockout of both is required for a lethal phenotype. Interestingly, U1A associates with U2 RNA when U2B'' is deleted. Thus, the two members of this gene family normally function as components of different snRNPs but apparently remain capable of performing the function of the other. Redundancy results from the fact that one protein can substitute for the other, even though it normally does not.
Saldi T, Wilusz C, MacMorris M, Blumenthal T
Proceedings of the National Academy of Sciences of the United States of America
2007-06-05 00:00
104
23
9753-7
Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045
Proc. Natl. Acad. Sci. U.S.A.
0027-8424
10.1073/pnas.0701720104
0701720104
38
True
17535930
