The zinc fingers of the SR-like protein ZRANB2 are single-stranded RNA-binding domains that recognize 5' splice site-like sequencesLoughlin, F.E., Mansfield, R.E., Vaz, P.M., McGrath, A.P., Setiyaputra, S., Gamsjaeger, R., Chen, E.S., Morris, B.J., Guss, J.M., Mackay, J.P.
(2009) Proc.Natl.Acad.Sci.USA 106: 5581-5586
- PubMed: 19304800
- DOI: 10.1073/pnas.0802466106
- PubMed Abstract:
- Crystallization of a ZRANB2-RNA complex
Loughlin, F.E.,Lee, M.,Guss, J.M.,Mackay, J.P.
(2008) Acta Crystallogr.,Sect.F 64: 1175
The alternative splicing of mRNA is a critical process in higher eukaryotes that generates substantial proteomic diversity. Many of the proteins that are essential to this process contain arginine/serine-rich (RS) domains. ZRANB2 is a widely-expresse ...
The alternative splicing of mRNA is a critical process in higher eukaryotes that generates substantial proteomic diversity. Many of the proteins that are essential to this process contain arginine/serine-rich (RS) domains. ZRANB2 is a widely-expressed and highly-conserved RS-domain protein that can regulate alternative splicing but lacks canonical RNA-binding domains. Instead, it contains 2 RanBP2-type zinc finger (ZnF) domains. We demonstrate that these ZnFs recognize ssRNA with high affinity and specificity. Each ZnF binds to a single AGGUAA motif and the 2 domains combine to recognize AGGUAA(N(x))AGGUAA double sites, suggesting that ZRANB2 regulates alternative splicing via a direct interaction with pre-mRNA at sites that resemble the consensus 5' splice site. We show using X-ray crystallography that recognition of an AGGUAA motif by a single ZnF is dominated by side-chain hydrogen bonds to the bases and formation of a guanine-tryptophan-guanine "ladder." A number of other human proteins that function in RNA processing also contain RanBP2 ZnFs in which the RNA-binding residues of ZRANB2 are conserved. The ZnFs of ZRANB2 therefore define another class of RNA-binding domain, advancing our understanding of RNA recognition and emphasizing the versatility of ZnF domains in molecular recognition.
School of Molecular and Microbial Biosciences, University of Sydney, Sydney NSW 2006, Australia.