Selective repression of low-density lipoprotein receptor expression by SP600125: coupling of histone H3-Ser10 phosphorylation and Sp1 occupancy.
In this study, we show that exposure of human hepatocellular HepG2 cells to SP600125 rapidly and dramatically reduced global histone H3-Ser10 phosphorylation, without significantly affecting the global acetylation of neighboring lysines. The loss of phosphorylation is not due to changes in cell cycle distribution and/or apoptosis and is mediated independent of either p46/54(JNK) or MSK-1/2 inhibition. Moreover, SP600125 repressed the basal expression of the endogenous LDL receptor in a gene-specific manner, whereas the expression of squalene synthase, sterol response element-binding protein-1, and beta-actin was not altered by SP600125. Finally, chromatin immunoprecipitation and in vivo footprinting assays provided direct evidence that localized histone H3-Ser10 dephosphorylation at the low-density lipoprotein receptor promoter was associated with a significant decrease in the occupancy of the Sp1 binding site, with a slight reduction in the occupancy of RNA polymerase II. Together, our findings show that SP600125 is an efficient inhibitor of histone H3-Ser10 phosphorylation in vivo, and our results led us to hypothesize that this modification plays a novel role in regulating transcriptional control by modulating promoter accessibility to maintain basal expression in a gene-specific manner.
Huang
Wei
W
Department of Molecular and Cellular Biochemistry, The Ohio State University College of Medicine and Public Health, and The Dorothy M. Davis Heart and Lung Research Institute, Columbus, OH 43210, USA.
Batra
Sanjay
S
Korrapati
Sasi
S
Mishra
V
V
Mehta
Kamal D
KD
D000873:Anthracenes / Q000494:pharmacology*; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002453:Cell Cycle; D002460:Cell Line; D004247:DNA / Q000235:genetics / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D006657:Histones / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008954:Models, Biological; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011973:Receptors, LDL / Q000235:genetics*; D012694:Serine / Q000737:chemistry; D016329:Sp1 Transcription Factor / Q000378:metabolism*
D000873:Anthracenes; D006657:Histones; D011973:Receptors, LDL; D016329:Sp1 Transcription Factor; C432165:pyrazolanthrone; D012694:Serine; D004247:DNA; D048049:Extracellular Signal-Regulated MAP Kinases