Abstract
Nonsense mutations influence several aspects of gene expression, including mRNA stability and splicing fidelity, but the mechanism by which premature termination codons (PTCs) can apparently affect splice-site selection remains elusive. We used a model human β-globin gene with duplicated 5′ splice sites (5′ss) and found that PTCs inserted between the two 5′ss do not directly influence splicing in this system. Instead, their apparent effect on 5′ss selection in vivo is an indirect result of nonsense-mediated mRNA decay (NMD), as conditions that eliminated NMD also abrogated the effect on splicing. Remarkably, we found an unexpected function of SR proteins in targeting several mRNAs with PTCs to the NMD pathway. Overexpression of various SR proteins strongly enhanced NMD, and this effect required an RS domain. Our data argue against a universal role of PTCs in regulating pre-mRNA splicing and reveal an additional function of SR proteins in eukaryotic gene expression.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
