A novel POU family transcription factor is closely related to Brn-3 but has a distinct expression pattern in neuronal cells

Abstract

The use of the polymerase chain reaction in conjunction with degenerate oligonucleotides has allowed the isolation of cDNA clones derived from each of the POU family transcription factors expressed in the proliferating ND7 neuronal cell line. In addition to the previously characterized Oct-1, Oct-2 and Brn-3 factors, ND7 cells have been shown by this means to express a novel POU factor. This factor is closely related to Brn-3 but differs at seven amino acids in the POU domain, one of which is located in a region which is critical for protein-protein interactions between different POU proteins. Like Brn-3, the novel factor is expressed at high levels in embryonic brain and declines in abundance during neuronal development. In contrast to Brn-3 however, it is absent in mature sensory neurons and its expression declines during the in vitro differentiation of ND7 cells to a non-dividing phenotype whilst Brn-3 expression increases. The significance of these distinct but overlapping expression patterns is discussed in terms of the possible role of these two factors in regulating neuronal gene expression.

The Brn-3b POU family transcription factor represses expression of the BRCA-1 anti-oncogene in breast cancer cells

“…Membranes were exposed to ®lms, (Eastman Kodak Co., Rochester, NY, USA) and the subsequent autoradiographs were then analysed using a densitometer (Bio-Rad Laboratories, Hercules, CA, USA). We have previously shown that this blotting procedure, in conjunction with the RT ± PCR conditions used, allows accurate quanti®cation of the Brn-3a and Brn-3b mRNAs relative to the constitutively expressed cyclophilin mRNA (Lillycrop et al, 1992;Ndisang et al, 1998;Morris et al, 1994).…”

“…Brn-3a, Brn-3b and Brn-3c are closely related members of the POU family which are encoded by di erent genes (Theil et al, 1993) and are expressed in distinct but overlapping patterns in the developing and adult nervous system (He et al, 1989;Gerrero et al, 1993;Lillycrop et al, 1992;Turner et al, 1994;Ninkina et al, 1993). In addition however, expression of Brn-3a and Brn-3b has also been detected in some non neuronal cells such as cervical epithelium (Lillycrop et al, 1992;Ndisang et al, 1998) and in the testis (Budhram-Mahadeo et al, submitted).…”

“…In addition however, expression of Brn-3a and Brn-3b has also been detected in some non neuronal cells such as cervical epithelium (Lillycrop et al, 1992;Ndisang et al, 1998) and in the testis (Budhram-Mahadeo et al, submitted).…”

NT-3 regulates expression of Brn3a but not Brn3b in developing mouse trigeminal sensory neurons

“…The Brn3 subfamily of POU domain factors contains three members, Brn3a, Brn3b and Brn3c, that have also been termed Brn-3.0, Brn-3.2 and Brn-3.1, respectively w x 17, 18,23,32,36,44 . Since the Brn3 family are the most closely related factors to unc86, they may be the mammalian homologues of this gene and therefore may play a role in the determination of neuronal phenotype.…”

The cellular transcription factor Brn-3a and the smoking-related substance nicotine interact to regulate the activity of the HPV URR in the cervix

“…In particular, Brn-3a is member of the POU family of cellular transcription factors, which binds to a specific motif of the HPV URR and strongly stimulates its activity (Lillycrop et al, 1992;Morris et al, 1994). We have shown in previous studies that Brn-3a is overexpressed in human cervical carcinoma biopsies (Ndisang et al, 2000;Sindos et al, 2003a, b), and that the inhibition of its expression in human cervical cancer cells abrogates HPV gene expression and reduces cellular growth and anchorage independence in vitro, as well as the ability to form tumours in vivo (Ndisang et al, 1999(Ndisang et al, , 2001).…”