Regulation of IkappaBbeta expression in testis.
IkappaBalpha and IkappaBbeta are regulators of the nuclear factor-kappaB (NF-kappaB) transcription factor family. Both IkappaBs bind to the same NF-kappaB dimers and are widely expressed in different cells and tissues. To better understand how these two IkappaB isoforms differ biologically, we have characterized the expression of IkappaBbeta in testis, a tissue in which IkappaBalpha is only minimally expressed. We have found that IkappaBbeta expression is localized within the haploid spermatid stages of spermatogenesis and follows the expression of nuclear NF-kappaB. IkappaBbeta expression in haploid spermatids is likely regulated by Sox family proteins, members of which are also expressed within spermatids. We have shown that both SRY and Sox-5 can bind to multiple Sox binding sites found within the IkappaBbeta promoter and can enhance transcription of a reporter gene in transient transfection assays. We also demonstrate that IkappaBbeta mRNA is strongly expressed in developing male gonads. These results therefore suggest that IkappaBbeta may be a novel target for transcription factors of the HMG-box SRY/Sox family and imply a potential role for NF-kappaB/IkappaBbeta in spermatogenesis.
Budde
Lucy M
LM
Section of Immunobiology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
Wu
Chun
C
Tilman
Christopher
C
Douglas
Iris
I
Ghosh
Sankar
S
D000818:Animals; D001665:Binding Sites; D015152:Blotting, Northern; D002417:Cattle; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006238:Haploidy; D006367:HeLa Cells; D006801:Humans; D020672:I-kappa B Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D017403:In Situ Hybridization; D008156:Luciferases / Q000378:metabolism; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D008957:Models, Genetic; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000378:metabolism; D055755:SOXD Transcription Factors; D013087:Spermatids / Q000378:metabolism; D013094:Spermatozoa / Q000378:metabolism; D013737:Testis / Q000378:metabolism*; D013997:Time Factors; D014018:Tissue Distribution; D014157:Transcription Factors; D014158:Transcription, Genetic; D014162:Transfection
D004268:DNA-Binding Proteins; C083487:I kappa B beta protein; D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606204:NFKBIA protein, human; C000606205:Nfkbia protein, mouse; D009687:Nuclear Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; C490301:SOX5 protein, human; D055755:SOXD Transcription Factors; C089186:Sox5 protein, mouse; D014157:Transcription Factors; D000072000:NF-KappaB Inhibitor alpha; D008156:Luciferases