A Highly Conserved GAD-1 Is Required for Pre-mRNA Splicing and Transcription Elongation by Forming Spliceosome with NineTeen Complex

ABSTRACT: Pre-mRNA splicing requires assembly of spliceosome that consists of hundreds of factors forming various dynamic complexes with or without small nuclear RNAs (snRNAs). Systematic identification of the splicing factors remains a significant challenge especially in vivo. In our genetic screening for the factors required for division asynchrony during Caenorhabditis elegans embryogenesis, we identified a highly conserved but uncharacterized essential protein, GAD-1, that is necessary for setting cell cycle length of intestine progenitors, a function that is shared with many other factors involved in transcription, pre-mRNA splicing or polyadenylation, suggesting its potential role in mRNA biogenesis. Co-immunoprecipitation followed by mass spectrometry reveals that GAD-1 mainly interacts with non-snRNP type of splicing complex called NineTeen Complex (NTC). Consistent with this, RNA-seq analysis demonstrates pervasive defects in pre-mRNA splicing in gad-1 mutants. Transgenic reporter assay shows its ubiquitous and nuclear expression across developmental stages. Immunostaining of the C-terminal domain of RNA polymerase II demonstrates a GAD-1’s role in transcription elongation. In agreement with this, depletion of GAD-1 and its interacting partners inhibits expression of both ubiquitous and tissue-specific genes, supporting that both GAD-1 and many of its interacting proteins are novel components of NTC or its associated spliceosome. Taken together, we identify GAD-1 and its multiple interacting partners as novel components of spliceosome in vivo through which they regulate pre-mRNA splicing and transcription elongation. 

ORGANISM(S): Caenorhabditis elegans

PROVIDER: GSE94463 | GEO | 2017/12/31

SECONDARY ACCESSION(S): PRJNA369783

REPOSITORIES: GEO