Transcriptomic comparison of Drosophila snRNP biogenesis mutants reveals mutant-specific changes in pre-mRNA processing: implications for spinal muscular atrophy.
Survival motor neuron (SMN) functions in the assembly of spliceosomal small nuclear ribonucleoproteins (snRNPs) that catalyze pre-mRNA splicing. Here, we used disruptions in Smn and two additional snRNP biogenesis genes, Phax and Ars2, to classify RNA processing differences as snRNP-dependent or gene-specific in Drosophila Phax and Smn mutants exhibited comparable reductions in snRNAs, and comparison of their transcriptomes uncovered shared sets of RNA processing changes. In contrast, Ars2 mutants displayed only small decreases in snRNA levels, and RNA processing changes in these mutants were generally distinct from those identified in Phax and Smn animals. Instead, RNA processing changes in Ars2 mutants support the known interaction of Ars2 protein with the cap-binding complex, as splicing changes showed a clear bias toward the first intron. Bypassing disruptions in snRNP biogenesis, direct knockdown of spliceosomal proteins caused similar changes in the splicing of snRNP-dependent events. However, these snRNP-dependent events were largely unaltered in three Smn mutants expressing missense mutations that were originally identified in human spinal muscular atrophy (SMA) patients. Hence, findings here clarify the contributions of Phax, Smn, and Ars2 to snRNP biogenesis in Drosophila, and loss-of-function mutants for these proteins reveal differences that help disentangle cause and effect in SMA model flies.
Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
Eric L
EL
Garcia
Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
Ying
Y
Wen
Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
Kavita
K
Praveen
Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
A Gregory
AG
Matera
D017398:Alternative Splicing; D000818:Animals; D004330:Drosophila / Q000378:metabolism*; D009134:Muscular Atrophy, Spinal / Q000235:genetics*; D020125:Mutation, Missense; D012322:RNA Precursors / Q000235:genetics*; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000235:genetics*; D017411:Ribonucleoproteins, Small Nuclear / Q000378:metabolism*; D059467:Transcriptome
D012322:RNA Precursors; D012333:RNA, Messenger; D017411:Ribonucleoproteins, Small Nuclear
Abelson interacting protein; Ars2; GARS; PHAX; Prp6; Prp8; RNA-sequencing; SMA; SMN; alternative polyadenylation; alternative splicing; dUTPase; phosphorylated adaptor for RNA export; snRNA; snRNP biogenesis; spinal muscular atrophy; survival motor neuron; αCOP