Zebrafish pou[c]: a divergent POU family gene ubiquitously expressed during embryogenesis.
We report the isolation and characterization of cDNA for a novel zebrafish (Brachyodanio rerio) POU domain gene, pou[c], which is ubiquitously expressed during embryonic development. This gene encodes a 610 amino acids long protein with a 149 amino acid POU domain ending only 8 residues before the C terminus. The 453 amino acids long region N-terminal to the POU domain contains several features typical of transcriptional activation domains such as an acidic region with a putative amphipathic alpha-helix, a glutamine-rich region, and short threonine- and/or serine-rich regions. Comparison of the POU domain of pou[c] to other known POU sequences clearly show that pou[c] has the most divergent POU domain sequence reported to date. Thus, we suggest that pou[c] should be placed as the presently sole member of a new, sixth class of POU proteins. DNA-binding studies revealed that pou[c] is not an octamer-binding transcription factor like the Oct proteins described from mammals, chicken and Xenopus. Rather, pou[c] binds with high affinity to the TAATGARAT motif found in the promoters of the herpes simplex virus immediate early genes and to degenerate octamer-TAATGA motifs. Circular permutation analyses also show that pou[c] induces DNA bending upon sequence-specific binding.
Johansen
T
T
Department of Biochemistry, University of Tromsø, Norway.
Moens
U
U
Holm
T
T
Fjose
A
A
Krauss
S
S
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D015152:Blotting, Northern; D004247:DNA; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D005810:Multigene Family; D009690:Nucleic Acid Conformation; D050809:POU Domain Factors; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology / Q000235:genetics*; D029961:Zebrafish Proteins
D004268:DNA-Binding Proteins; D050809:POU Domain Factors; D014157:Transcription Factors; D029961:Zebrafish Proteins; C079852:pou6f1 protein, zebrafish; D004247:DNA