Deletions of singular U1 snRNA gene significantly interfere with transcription and 3'-end mRNA formation rather than pre-mRNA splicing
To investigate the functions of each singular copy of snRNA genes in Drosophila melanogaster, we focused on the U1 snRNA and systematically investigated all the five Drosophila U1 genes. We constructed two series of U1-gene strains, one is transgenic strains of U1 promoter-driven gfp that allows for detection of each U1-gene's expression in various developmental stages and tissues, the other is the CRISPR/Cas9-mediated precise U1-gene deletion strains that allows for investigation of phenotypes and effects on multiple RNA processing steps, including transcription, splicing and 3'-end formation. Further in vitro pulldown assay reveal the Drosophila U1 variants have different activity in binding with Sm proteins. Overall design: Comparatively analysis the differentially expressed genes, alternative polyadenylation events and alternative splicing events of RNA-Seq data for WT and detection of each U1-gene's expression in Drosophila melanogaster.