| First Author | Wu K | Year | 1993 |
| Journal | J Cell Biochem | Volume | 52 |
| Issue | 4 | Pages | 449-62 |
| PubMed ID | 7901228 | Mgi Jnum | J:33000 |
| Mgi Id | MGI:80488 | Doi | 10.1002/jcb.240520409 |
| Citation | Wu K, et al. (1993) Protein product of the somatic-type transcript of the Hoxa-4 (Hox-1.4) gene binds to homeobox consensus binding sites in its promoter and intron. J Cell Biochem 52(4):449-62 |
| abstractText | The murine Hoxa-4 gene encodes a protein with a homeodomain closely related to those produced by the Antennapedia-like class of Drosophila genes. Drosophila homeodomain proteins can function as transcription factors, binding to several specific DNA sequences. One sequence that is frequently encountered contains a core ATTA motif within a larger consensus sequence, such as CAATTAA. The in vitro synthesized protein product of Hoxa-4 was shown to bind to a subset of restriction fragments of the Hoxa-4 gene itself as determined by gel retardation experiments. Direct examination of the sequences of the fragments bound by Hoxa-4 protein revealed the presence of four regions containing the core ATTA motif. Two regions contained sequences of the CAATTAA class and were located approximately 1 kb upstream from the putative somatic Hoxa-4 promoter and within the intron. Two additional binding sites containing the consensus target sequence involved in autoregulation of Drosophila Deformed gene were identified: one immediately downstream of the putative embryonic transcription start site and one within the intron, respectively. Specific binding of the in vitro produced Hoxa-4 protein to oligonucleotides corresponding to these sequences was observed in gel retardation assays. The same results were obtained with Hoxa-4 protein produced in a Baculovirus expression system. Experiments using oligonucleotides containing base substitutions in positions 1, 3, 4, and 5 in the sequence CAATTAA showed severely reduced binding. The use of truncated mutant Hoxa-4 proteins in gel retardation assays and in transient co-transfection experiments revealed that the intact homeodomain was required for the binding. These results also suggested that the Hoxa-4 gene has the potential to auto-regulate its expression by interacting with the homeodomain binding sites present in the promoter as well as in the intron. |
