Structure-function analysis of the 5′ end of yeast U1 snRNA highlights genetic interactions with the Msl5Mud2 branchpoint-binding complex and other spliceosome assembly factors Journal Article


Authors: Schwer, B.; Chang, J.; Shuman, S.
Article Title: Structure-function analysis of the 5′ end of yeast U1 snRNA highlights genetic interactions with the Msl5Mud2 branchpoint-binding complex and other spliceosome assembly factors
Abstract: Yeast pre-mRNA splicing initiates via formation of a complex comprising U1 snRNP bound at the 50 splice site (50SS) and the Msl5 • Mud2 heterodimer engaged at the branchpoint (BP). Here, we present a mutational analysis of the U1 snRNA, which shows that although enlarging the 50 leader between the TMG cap and the 3ACUUAC8 motif that anneals to the 50SS is tolerated, there are tight constraints on the downstream spacer between 3ACUUAC8 and helix 1 of the U1 fold. We exploit U1 alleles with 50 extensions, variations in the 3ACUUAC8 motif, downstream mutations and a longer helix 1 to discover new intra-snRNP synergies with U1 subunits Nam8 and Mud1 and the trimethylguanosine (TMG) cap. We describe novel mutations in U1 snRNA that bypass the essentiality of the DEAD-box protein Prp28. Structure-guided mutagenesis of Msl5 distinguished four essential amino acids that contact the BP sequence from nine other BP-binding residues that are inessential. We report new synthetic genetic interactions of the U1 snRNP with Msl5 and Mud2 and with the nuclear capbinding subunit Cbc2. Our results fortify the idea that spliceosome assembly can occur via distinct genetically buffered microscopic pathways involving cross-intron-bridging interactions of the U1 snRNP • 50SS complex with the Mud2 • Msl5 • BP complex. © 2013 The Author(s).
Journal Title: Nucleic Acids Research
Volume: 41
Issue: 15
ISSN: 0305-1048
Publisher: Oxford University Press  
Date Published: 2013-08-01
Start Page: 7485
End Page: 7500
Language: English
DOI: 10.1093/nar/gkt490
PROVIDER: scopus
PMCID: PMC3753624
PUBMED: 23754852
DOI/URL:
Notes: --- - "Export Date: 1 October 2013" - "CODEN: NARHA" - "Source: Scopus"
Altmetric
Citation Impact
MSK Authors
  1. Stewart H Shuman
    514 Shuman
  2. Jonathan Chang
    6 Chang