The closely related POU family transcription factors Brn-3a and Brn-3b are expressed in distinct cell types in the testis.
Although the Brn-3a and Brn-3b POU family transcription factors were originally identified in neuronal cells, their expression in some non neuronal cell types has previously been reported. Here we report that Brn-3a and Brn-3b are also expressed in the testis with expression of each factor being observed at distinct stages of germ cell development. Thus, Brn-3a is expressed in spermatogonia whereas Brn-3b expression is observed in post-meiotic spermatids. In agreement with this, Brn-3a expression is detectable much earlier than that of Brn-3b in testes derived from sexually immature postnatal animals. Similarly, Brn-3b expression is absent in knock out mice lacking a functional CREM transcription factor in which the later stages of germ cell development do not occur, whereas Brn-3a expression is observed at similar levels in the testes of these knock out mice. Interestingly, the cellular pattern of Brn-3a expression during germ cell development coincides with that of the BRCA-1 anti-oncogene. Consistent with the possibility that Brn-3a may regulate expression of BRCA-1 in the testis, we have shown that Brn-3a can strongly activate the BRCA-1 promoter in co-transfection experiments whereas Brn-3b does not have this effect. Hence, as observed in neuronal cells, Brn-3a and Brn-3b may play distinct and important functional roles in the regulation of gene expression during germ cell development.
Budhram-Mahadeo
V
V
Medical Molecular Biology Unit, Institute of Child Health, University College London, 30 Guilford Street, WC1N 1EH, London, UK.
Moore
A
A
Morris
P J
PJ
Ward
T
T
Weber
B
B
Sassone-Corsi
P
P
Latchman
D S
DS
D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D051786:Cyclic AMP Response Element Modulator; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D019398:Genes, BRCA1 / Q000235:genetics / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D050809:POU Domain Factors; D051381:Rats; D017207:Rats, Sprague-Dawley; D012097:Repressor Proteins / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013087:Spermatids / Q000276:immunology / Q000378:metabolism*; D013093:Spermatogonia / Q000254:growth & development / Q000276:immunology / Q000378:metabolism*; D013737:Testis / Q000166:cytology / Q000378:metabolism*; D014018:Tissue Distribution; D050818:Transcription Factor Brn-3; D050819:Transcription Factor Brn-3A; D050820:Transcription Factor Brn-3B; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
D004268:DNA-Binding Proteins; D050809:POU Domain Factors; C494188:POU4F1 protein, human; C494190:POU4F2 protein, human; C494189:Pou4f1 protein, mouse; D012097:Repressor Proteins; D050818:Transcription Factor Brn-3; D050819:Transcription Factor Brn-3A; D050820:Transcription Factor Brn-3B; D014157:Transcription Factors; D051786:Cyclic AMP Response Element Modulator