Negative regulation of STAT92E by an N-terminally truncated STAT protein derived from an alternative promoter site.
Previously unrecognized mRNAs originating from a dual promoter at the stat92E locus are described. One of these encodes a truncated protein, DeltaNSTAT92E, that lacks the N-terminal 133 amino acids. Antibodies detect both the full-length and truncated molecules early in embryogenesis (1-5 h), and mRNA detection by specific RT-PCR reactions accords with the protein distribution. Given that the N termini of mammalian STATs are known to have positive functions in transcriptional activation, we explored the role of DeltaNSTAT92E early in embryogenesis. By increasing the DeltaNSTAT92E-to-STAT92E ratio in overexpression and RNAi experiments, we observe phenotypes compatible with suppression of wild-type STAT92E activity. We therefore conclude that the short form of STAT92E is a naturally occurring dominant-negative product that can be added to the growing list of negative regulators of STAT activity.
Henriksen
Melissa A
MA
Laboratory of Molecular Cell Biology, The Rockefeller University, New York, New York 10021, USA.
Betz
Aurel
A
Fuccillo
Marc V
MV
Darnell
James E
JE
D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004247:DNA / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D050791:STAT Transcription Factors; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D012333:RNA, Messenger; D050791:STAT Transcription Factors; C105675:Stat92E protein, Drosophila; D015534:Trans-Activators; D004247:DNA