Transcriptional activation of human 12-lipoxygenase gene promoter is mediated through Sp1 consensus sites in A431 cells - PubMed (original) (raw)

Transcriptional activation of human 12-lipoxygenase gene promoter is mediated through Sp1 consensus sites in A431 cells

Y W Liu et al. Biochem J. 1997.

Abstract

The functional 5' flanking region of the human 12-lipoxygenase in epidermoid carcinoma A431 cells was characterized. By a primer extension method, the transcription initiation sites were mapped at -47 adenosine, -48 guanosine and -55 guanosine upstream of the ATG translation start codon. Transient transfection with a series of 5' and 3' deletion constructs showed that the 5' flanking region spanning from -224 to -100 bp was important for the basal expression of 12-lipoxygenase gene. Gel mobility shift assays with antibodies of transcription factors showed that both Sp1 and Sp3 required highly GC-rich Sp1 sites within this region for binding. Disruption of two Sp1 recognition motifs residing at -158 to -150 bp and -123 to -114 bp by site-directed mutagenesis markedly reduced the basal 12-lipoxygenase promoter activity and abolished the retarded bands in a gel-shift assay, indicating that these two Sp1-binding sites were essential for gene expression. The same two Sp1-binding sites in this promoter region were also responsible for epidermal growth factor (EGF)-induced expression of 12-lipoxygenase gene. Moreover, EGF also induced the transcriptional activation of luciferase driven by SV40 early promoter, which contained rich Sp1-binding sites. Taken together, the results suggest that two specific Sp1 consensus sites are involved in the mediation of the basal promoter activity as well as EGF induction of the 12-lipoxygenase gene and that Sp1 and Sp3 transcription factors might have a role in their regulation.

PubMed Disclaimer

Similar articles

Cited by

References

    1. FEBS Lett. 1995 Apr 17;363(1-2):105-10 - PubMed
    1. J Biol Chem. 1995 Nov 10;270(45):26993-9 - PubMed
    1. Biochim Biophys Acta. 1997 Jan 7;1344(1):38-46 - PubMed
    1. Biochim Biophys Acta. 1997 Feb 18;1344(3):270-7 - PubMed
    1. Proc Natl Acad Sci U S A. 1974 Sep;71(9):3400-4 - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources