SMAUG is a major regulator of maternal mRNA destabilization in Drosophila and its translation is activated by the PAN GU kinase.
In animals, egg activation triggers a cascade of posttranscriptional events that act on maternally synthesized RNAs. We show that, in Drosophila, the PAN GU (PNG) kinase sits near the top of this cascade, triggering translation of SMAUG (SMG), a multifunctional posttranscriptional regulator conserved from yeast to humans. Although PNG is required for cytoplasmic polyadenylation of smg mRNA, it regulates translation via mechanisms that are independent of its effects on the poly(A) tail. Analyses of mutants suggest that PNG relieves translational repression by PUMILIO (PUM) and one or more additional factors, which act in parallel through the smg mRNA's 3' untranslated region (UTR). Microarray-based gene expression profiling shows that SMG is a major regulator of maternal transcript destabilization. SMG-dependent mRNAs are enriched for gene ontology annotations for function in the cell cycle, suggesting a possible causal relationship between failure to eliminate these transcripts and the cell cycle defects in smg mutants.
Tadros
Wael
W
Graduate Department of Molecular and Medical Genetics, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada.
Goldman
Aaron L
AL
Babak
Tomas
T
Menzies
Fiona
F
Vardy
Leah
L
Orr-Weaver
Terry
T
Hughes
Timothy R
TR
Westwood
J Timothy
JT
Smibert
Craig A
CA
Lipshitz
Howard D
HD
D020413:3' Untranslated Regions / Q000378:metabolism; D000818:Animals; D019295:Computational Biology; D003593:Cytoplasm / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000196:embryology / Q000235:genetics* / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000166:cytology; D005260:Female; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D006360:Heat-Shock Proteins / Q000235:genetics; D046228:Microarray Analysis; D008957:Models, Genetic; D009154:Mutation / Q000235:genetics; D010063:Ovum; D026723:Polyadenylation; D014176:Protein Biosynthesis; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D020871:RNA Stability; D023121:RNA, Messenger, Stored / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*
D020413:3' Untranslated Regions; D029721:Drosophila Proteins; D006360:Heat-Shock Proteins; C089272:Hsp83 protein, Drosophila; D023121:RNA, Messenger, Stored; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; C402587:smg protein, Drosophila; C417221:png protein, Drosophila; D017346:Protein Serine-Threonine Kinases