Transcriptional regulation of the murine 1-cys peroxiredoxin gene by the B cell-specific activator protein, Pax5.
Pax5, a member of the paired box gene family of transcription factors, is a B cell-specific activator protein (BSAP) that plays important roles in controlling the expression of lineage- and differentiation-stage specific genes during B lymphopoiesis. We identified two putative Pax5 binding sites in a 668 bp of the murine 1-cys peroxiredoxin (1-cysPrx) promoter region. These sites were located at positions -278 to -262 and -50 to -34 from the translation start site. Gel mobility shift assays showed that recombinant Pax5 protein bound specifically to the nucleotide regions -56 to -24 (MP1 probe) and -284 to -253 (MP2 probe). Furthermore, endogenous Pax5 protein from B lymphoblast cells (IM-9) formed a DNA-protein complex with MP1 and MP2 probes, indicating that Pax5 binding occurs specifically at these sequences in vivo. Transient transfection studies showed that expression of exogenous Pax5 resulted in dose-dependent increases in 1-cysPrx promoter activity, implying that Pax5 functions as a positive transcription factor for 1-cysPrx expression. Further transient cotransfection studies showed that coexpression of Pax5 and histone acetyltransferases (HATs), such as p300, cAMP-response-element-binding protein (CBP) and p300/CBP associated factor (PCAF) enhanced the Pax5-mediated 1-cysPrx promoter activity. Immunoprecipitation studies indicated that Pax5 directly binds to HATs. Chromatin immunoprecipitation assays showed that the recruitment of Pax5 to the promoter induced histone H3 and H4 hyperacetylation of chromatin. Lipopolysaccharides (LPS) stimulation of murine splenocytes resulted in coordinated expression of Pax5 and 1-cysPrx proteins. These findings suggest that Pax5 may function as a transactivator of 1-cysPrx gene expression.
Lee
In-Seon
IS
Department of Life Science, College of Natural Sciences, Chung-Ang University, Seoul 156-756, Korea.
Choi
Won Ho
WH
Kim
Ji Young
JY
Jeong
Jin-Yong
JY
Kim
Mi-Jung
MJ
Nam
Joo-Hyun
JH
Kim
Jong-Hyeok
JH
Seo
Sang-Beom
SB
Pak
Jhang Ho
JH
D000107:Acetylation; D000818:Animals; D001665:Binding Sites; D005786:Gene Expression Regulation; D051548:Histone Acetyltransferases / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D051379:Mice; D051757:PAX5 Transcription Factor / Q000378:metabolism / Q000502:physiology*; D054464:Peroxiredoxins / Q000235:genetics*; D011401:Promoter Regions, Genetic; D013154:Spleen / Q000166:cytology; D014158:Transcription, Genetic
D006657:Histones; D051757:PAX5 Transcription Factor; C497282:Pax5 protein, mouse; D054464:Peroxiredoxins; C489899:Prdx1 protein, mouse; D051548:Histone Acetyltransferases