Evidence that noncoding RNA dutA is a multicopy suppressor of Dictyostelium discoideum STAT protein Dd-STATa.
Dd-STATa, a Dictyostelium discoideum homologue of metazoan STAT transcription factors, is necessary for culmination. We created a mutant strain with partial Dd-STATa activity and used it to screen for unlinked suppressor genes. We screened approximately 450,000 clones from a slug-stage cDNA library for their ability to rescue the culmination defect when overexpressed. There were 12 multicopy suppressors of Dd-STATa, of which 4 encoded segments of a known noncoding RNA, dutA. Expression of dutA is specific to the pstA zone, the region where Dd-STATa is activated. In suppressed strains the expression patterns of several putative Dd-STATa target genes become similar to the wild-type strain. In addition, the amount of the tyrosine-phosphorylated form of Dd-STATa is significantly increased in the suppressed strain. These results indicate that partial copies of dutA may act upstream of Dd-STATa to regulate tyrosine phosphorylation by an unknown mechanism.
Shimada
Nao
N
Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan.
Kawata
Takefumi
T
D000818:Animals; D004023:Dictyostelium / Q000235:genetics / Q000378:metabolism; D017125:Genes, Protozoan; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D022661:RNA, Untranslated / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D050791:STAT Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism
D035683:MicroRNAs; D015800:Protozoan Proteins; D012322:RNA Precursors; D034741:RNA, Small Interfering; D022661:RNA, Untranslated; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D050791:STAT Transcription Factors; C426583:STATa protein, Dictyostelium; D014443:Tyrosine