The KH-type RNA-binding protein PSI is required for Drosophila viability, male fertility, and cellular mRNA processing.
Direct interactions between RNA-binding proteins and snRNP particles modulate eukaryotic pre-mRNA processing patterns to control gene expression. Here, we report that the conserved U1 snRNP-interacting RNA-binding protein PSI is essential for Drosophila viability. A null PSI mutation is recessive lethal at the first-instar larval stage, and lethality is fully rescued by transgenes expressing the PSI protein. A mutant transgene that lacks the PSI-U1 snRNP-interaction domain restores viability but shows courtship behavior abnormalities and meiosis defects during spermatogenesis, resulting in a complete male sterility phenotype. Using cDNA microarrays, we have identified specific target mRNAs with altered expression profiles in these mutant males. A subset of these transcripts is also found associated with PSI in endogenous immunopurified ribonucleoprotein complexes. One specific target, the hrp40/squid transcript, shows an altered pre-mRNA splicing pattern in PSI mutant testes. We conclude that a functional association between the PSI protein and the spliceosomal U1 snRNP particle is required for normal Drosophila development and for the processing of specific PSI-interacting cellular transcripts. These results also validate the use of cDNA microarrays to characterize in vivo RNA-processing defects and alternative pre-mRNA splicing patterns.
Labourier
Emmanuel
E
Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA.
Blanchette
Marco
M
Feiger
Jennie W
JW
Adams
Melissa D
MD
Rio
Donald C
DC
D000818:Animals; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000502:physiology*; D005298:Fertility / Q000235:genetics; D005786:Gene Expression Regulation / Q000502:physiology; D008297:Male; D009687:Nuclear Proteins; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000502:physiology*; D017411:Ribonucleoproteins, Small Nuclear / Q000502:physiology; D013091:Spermatogenesis / Q000235:genetics
D029721:Drosophila Proteins; D009687:Nuclear Proteins; C092281:PSI protein, Drosophila; D012322:RNA Precursors; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D017411:Ribonucleoproteins, Small Nuclear