Transcription intermediary factor 1I[sup3 decreases protein expression of the transcriptional cofactor, LIM-domain-binding 1

LIM-domain-binding 1 (LDB1) is a cofactor that participates in formation of regulatory complexes involving transcription factors containing LIM domains as well as other factors. We have examined the ability of transcriptional intermediary factor 1I[sup3 (TIF1I[sup3) to decrease LDB1 expression. An e...

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Bibliographic Details
Published in:Biochemical and biophysical research communications 2010-06, Vol.396 (3), p.674-678
Main Authors: Howard, Paul W, Ransom, David G, Maurer, Richard A
Format: Article
Language:English
Subjects:
Danio rerio
Freshwater
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Summary:LIM-domain-binding 1 (LDB1) is a cofactor that participates in formation of regulatory complexes involving transcription factors containing LIM domains as well as other factors. We have examined the ability of transcriptional intermediary factor 1I[sup3 (TIF1I[sup3) to decrease LDB1 expression. An expression vector for TIF1I[sup3 was found to decrease expression of LDB1. A mutation which disrupts the ubiquitin ligase activity of TIF1I[sup3 was found to block the ability of TIF1I[sup3 to decrease LDB1 expression. Proteasome inhibitors were also able to block TIF1I[sup3 effects on LDB1. Immunoprecipitation studies provided evidence that LDB1 interacts with TIF1I[sup3 in intact cells. Knockdown of TIF1I[sup3 in zebrafish embryos led to increased expression of LDB1 providing evidence for a physiological role of TIF1I[sup3 in regulating LDB1 expression. Reporter gene assays demonstrated that TIF1I[sup3 can alter the activity of LIM-homeodomain transcription factor-responsive promoters. These studies are consistent with a model in which TIF1I[sup3 acts to ubiquitinate LDB1 leading to degradation of LDB1 and changes in transcription of LDB1-dependent promoters.
ISSN:0006-291X
DOI:10.1016/j.bbrc.2010.04.160