TY - JOUR
T1 - SF3B1/Hsh155 HEAT motif mutations affect interaction with the spliceosomal ATPase Prp5, resulting in altered branch site selectivity in pre-mRNA splicing
AU - Tang, Qing
AU - Rodriguez-Santiago, Susana
AU - Wang, Jing
AU - Pu, Jia
AU - Yuste, Andrea
AU - Gupta, Varun
AU - Moldón, Alberto
AU - Xu, Yong Zhen
AU - Query, Charles C.
N1 - Publisher Copyright:
© 2016 Tang et al.
PY - 2016/12/15
Y1 - 2016/12/15
N2 - Mutations in the U2 snRNP component SF3B1 are prominent in myelodysplastic syndromes (MDSs) and other cancers and have been shown recently to alter branch site (BS) or 3′splice site selection in splicing. However, the molecular mechanism of altered splicing is not known. We show here that hsh155 mutant alleles in Saccharomyces cerevisiae, counterparts of SF3B1 mutations frequently found in cancers, specifically change splicing of suboptimal BS pre-mRNA substrates. We found that Hsh155p interacts directly with Prp5p, the first ATPase that acts during spliceosome assembly, and localized the interacting regions to HEAT (Huntingtin, EF3, PP2A, and TOR1) motifs in SF3B1 associated with disease mutations. Furthermore, we show that mutations in these motifs from both human disease and yeast genetic screens alter the physical interaction with Prp5p, alter branch region specification, and phenocopy mutations in Prp5p. These and other data demonstrate that mutations in Hsh155p and Prp5p alter splicing because they change the direct physical interaction between Hsh155p and Prp5p. This altered physical interaction results in altered loading (i.e., “fidelity”) of the BS–U2 duplex into the SF3B complex during prespliceosome formation. These results provide a mechanistic framework to explain the consequences of intron recognition and splicing of SF3B1 mutations found in disease.
AB - Mutations in the U2 snRNP component SF3B1 are prominent in myelodysplastic syndromes (MDSs) and other cancers and have been shown recently to alter branch site (BS) or 3′splice site selection in splicing. However, the molecular mechanism of altered splicing is not known. We show here that hsh155 mutant alleles in Saccharomyces cerevisiae, counterparts of SF3B1 mutations frequently found in cancers, specifically change splicing of suboptimal BS pre-mRNA substrates. We found that Hsh155p interacts directly with Prp5p, the first ATPase that acts during spliceosome assembly, and localized the interacting regions to HEAT (Huntingtin, EF3, PP2A, and TOR1) motifs in SF3B1 associated with disease mutations. Furthermore, we show that mutations in these motifs from both human disease and yeast genetic screens alter the physical interaction with Prp5p, alter branch region specification, and phenocopy mutations in Prp5p. These and other data demonstrate that mutations in Hsh155p and Prp5p alter splicing because they change the direct physical interaction between Hsh155p and Prp5p. This altered physical interaction results in altered loading (i.e., “fidelity”) of the BS–U2 duplex into the SF3B complex during prespliceosome formation. These results provide a mechanistic framework to explain the consequences of intron recognition and splicing of SF3B1 mutations found in disease.
KW - Disease mutation
KW - HEAT motif
KW - Pre-mRNA splicing fidelity
KW - Prp5
KW - SF3B1/Hsh155
UR - http://www.scopus.com/inward/record.url?scp=85009921491&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85009921491&partnerID=8YFLogxK
U2 - 10.1101/gad.291872.116
DO - 10.1101/gad.291872.116
M3 - Article
C2 - 28087715
AN - SCOPUS:85009921491
SN - 0890-9369
VL - 30
SP - 2710
EP - 2723
JO - Genes and Development
JF - Genes and Development
IS - 24
ER -