TY - JOUR
T1 - The human chorionic somatomammotropin gene enhancer is composed of multiple DNA elements that are homologous to several SV40 enhansons
AU - Jiang, Shi Wen
AU - Eberhardt, Norman L.
N1 - Copyright:
Copyright 2005 Elsevier B.V., All rights reserved.
PY - 1994/4/8
Y1 - 1994/4/8
N2 - Previous studies indicate that a human chorionic somatomammotropin (hCS) gene enhancer (CSEn) associated with the growth hormone (hGH) gene locus is involved in directing cell-specific expression of the hCS genes in placenta. In the current studies, we report a detailed structural analysis of this enhancer. CSEn stimulated transcription of a variety of promoters, including the hCS, human growth hormone, thymidine kinase, and Rous sarcoma virus promoters, in human choriocarcinoma cell lines (BeWo and JEG-3) but not HeLa cells or rat somatolactotrophes (GC). Maximal enhancer activity was confined to a 242-base pair DNA segment. Of several CSEn subfragments, only the En 57/242 subfragment retained activity (33.5% wild-type). The CSEn DNA sequence contained direct and inverted repeat motifs and sequences related to the SV40 enhansons, GT-IIC, GT-I, and SphI/SphII. DNase I footprint analysis revealed that most of these sites were protected by nuclear proteins derived from BeWo, JEG-3, HeLa, and GC cells. Site-specific block mutation of the GT-IIC- related and inverted repeat motifs virtually abolished enhancer activity, and mutation of all but the GT-I-related motif resulted in significant loss (30- 60%) of activity. These data demonstrate that the CS enhancer is comprised of multiple elements related to SV40 enhansons that interact cooperatively to generate enhancer function.
AB - Previous studies indicate that a human chorionic somatomammotropin (hCS) gene enhancer (CSEn) associated with the growth hormone (hGH) gene locus is involved in directing cell-specific expression of the hCS genes in placenta. In the current studies, we report a detailed structural analysis of this enhancer. CSEn stimulated transcription of a variety of promoters, including the hCS, human growth hormone, thymidine kinase, and Rous sarcoma virus promoters, in human choriocarcinoma cell lines (BeWo and JEG-3) but not HeLa cells or rat somatolactotrophes (GC). Maximal enhancer activity was confined to a 242-base pair DNA segment. Of several CSEn subfragments, only the En 57/242 subfragment retained activity (33.5% wild-type). The CSEn DNA sequence contained direct and inverted repeat motifs and sequences related to the SV40 enhansons, GT-IIC, GT-I, and SphI/SphII. DNase I footprint analysis revealed that most of these sites were protected by nuclear proteins derived from BeWo, JEG-3, HeLa, and GC cells. Site-specific block mutation of the GT-IIC- related and inverted repeat motifs virtually abolished enhancer activity, and mutation of all but the GT-I-related motif resulted in significant loss (30- 60%) of activity. These data demonstrate that the CS enhancer is comprised of multiple elements related to SV40 enhansons that interact cooperatively to generate enhancer function.
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M3 - Article
C2 - 8144621
AN - SCOPUS:0028276955
SN - 0021-9258
VL - 269
SP - 10384
EP - 10392
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 14
ER -