G-patch: a new conserved domain in eukaryotic RNA-processing proteins and type D retroviral polyproteins

Several eukaryotic proteins are associated with RNA processing 1 Staley J.P. Guthrie C. Cell. 1998; 92: 315-326 Abstract Full Text Full Text PDF PubMed Scopus (914) Google Scholar . These include the components of the spliceosome, the polyA-tail-specific complex and various regulatory heterogeneous nuclear ribonucleoprotein (hnRNP) and messenger RNP (mRNP) particles 1 Staley J.P. Guthrie C. Cell. 1998; 92: 315-326 Abstract Full Text Full Text PDF PubMed Scopus (914) Google Scholar , 2 Manley J.L. Curr. Opin. Genet. Dev. 1995; 5: 222-228 Crossref PubMed Scopus (80) Google Scholar , 3 Weighardt F. Biamonti G. Riva S. BioEssays. 1996; 18: 747-756 Crossref PubMed Scopus (180) Google Scholar . Systematic studies on these proteins have resulted in the identification of several distinct types of RNA-interacting modules. Such modules include the RNA-recognition motif (RRM) domain 4 Birney E. Kumar S. Krainer A.R. Nucleic Acids Res. 1993; 21: 5803-5816 Crossref PubMed Scopus (589) Google Scholar , the K-homology (KH) domain 5 Gibson T.J. Thompson J.D. Heringa J. FEBS Lett. 1993; 324: 361-366 Abstract Full Text PDF PubMed Scopus (174) Google Scholar , the tudor domain 6 Ponting C.P. Trends Biochem. Sci. 1997; 22: 51-52 Abstract Full Text PDF PubMed Scopus (176) Google Scholar and the double-stranded RNA-binding domain (dsRBD) 7 St Johnston D. et al. Proc. Natl. Acad. Sci. U. S. A. 1992; 89: 10979-10983 Crossref PubMed Scopus (486) Google Scholar . In addition, most of the RNA-processing proteins contain non-globular repeat segments, such as SR, RGG and GGY, which might play a role in subcellular targeting and non-specific RNA binding 4 Birney E. Kumar S. Krainer A.R. Nucleic Acids Res. 1993; 21: 5803-5816 Crossref PubMed Scopus (589) Google Scholar . The identification of these modules has provided insight into the specificity of RNA–protein interactions and allows the prediction of new RNA-binding proteins by sequence analysis. Here, a previously undetected domain that is present in several RNA-associated proteins and, unexpectedly, in type D retroviral polyproteins, is described. This domain, which we have called G-patch, after its characteristic, glycine-rich sequence signature, might be a new RNA-interacting module.