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Galectin‐4 is involved in p27‐mediated activation of the myelin basic protein promoter
Author(s) -
Wei Qiou,
EviatarRibak Tamar,
Keith Miskimins W.,
Miskimins Robin
Publication year - 2007
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2007.04488.x
Subject(s) - myelin basic protein , transcription factor , immunoprecipitation , biology , microbiology and biotechnology , chromatin immunoprecipitation , sp1 transcription factor , oligodendrocyte , gene expression , promoter , myelin , chemistry , gene , biochemistry , neuroscience , central nervous system
Our previous studies have found that expression of p27 in oligodendrocytes enhances myelin basic protein (MBP) gene expression through a mechanism that involves the transcription factor Sp1. In this study we show that this activation only requires the N‐terminal 45 amino acids of p27 containing a functional cyclin‐binding motif. In an effort to identify other cofactors that are involved in the p27‐mediated activation of MBP gene expression, a yeast two‐hybrid assay was performed using an N‐terminal truncated p27 and a mouse embryo cDNA library. Galectin‐4 was found to interact with p27 in the yeast two‐hybrid assay. This novel interaction was also confirmed using a glutathione‐S‐transferase interaction assay and immunoprecipitation assays. Expression of galectin‐4 in primary oligodendrocytes was confirmed by western blot. Additionally, the MBP promoter could be activated by expression of galectin‐4 in CG4 oligodendrocytes, similar to the effects of increased p27 levels. We also show that Sp1 and galectin‐4 interact in cells, while a complex of all three proteins could not be found. We conclude that galectin‐4 is involved in the p27‐mediated activation of the MBP gene, possibly through modulation of the glycosylation status of the transcription factor Sp1.