Endocrine Journal
Online ISSN : 1348-4540
Print ISSN : 0918-8959
ISSN-L : 0918-8959
Analysis of Possible Silencer Elements of Ovine Interferon-τ Gene
HIROHITO YAMAGUCHIMOMOKO KATSUMURAKAZUHIKO IMAKAWASENKITI SAKAIRONALD K. CHRISTENSON
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JOURNAL FREE ACCESS

2000 Volume 47 Issue 2 Pages 137-142

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Abstract

During the pen-implantation period significant production of ovine interferon-τ (oIFNτ) by the trophectoderm is detected in day 13-16 conceptuses, but its level rapidly declines thereafter. To understand molecular mechanisms by which oIFNτ gene expression is down-regulated, a variety of deletion constructs were prepared from upstream sequences of the oIFNτ gene and examined for possible silencer regions by using transient transfection into human choriocarcinoma, JEG3, cells. Two regions between -700 to -654 bases (distal region) and from -503 to -453 bases (proximal region) were found to be the possible negative regulatory regions. With probes prepared from these regions, gel mobility shift assay (GMSA) was then conducted. DNA-protein complexes were observed, but the gel shift pattern was different between nuclear extracts from days 14 (active oIFNτ production) and 20 (minute oIFNτ production) ovine trophoblasts. Day 20 nuclear extracts exhibited more band patterns than those of day 14; most notably the distal region between -692 and -668 bases exhibited the distinct band with nuclear extracts from day 20, but not from day 14 trophoblasts. In addition, the band patterns from day 20 trophoblast nuclear proteins were similar to those detected with JEG3 and HeLa cell nuclear extracts. Taken together, these observations suggest that the upstream sequences identified could serve as negative regulatory regions to which various nuclear factors bind, resulting in reduction of oIFNτ gene transcription.

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© The Japan Endocrine Society
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