共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
3.
P B Jones A G Miller D I Israel D R Galeazzi J P Whitlock 《The Journal of biological chemistry》1984,259(20):12357-12363
4.
A K Jaiswal L A Neuhold D W Nebert 《Biochemical and biophysical research communications》1987,148(2):857-863
Upstream sequences of the human P450IA1 gene were inserted into a promoterless expression vector (pSVO-cat) containing the chloramphenicol acetyltransferase (CAT) gene, with and without the Harvey murine sarcoma virus (Ha-MSV) core enhancer, and either plasmid was transfected into human breast carcinoma MCF-7 and MDA-231 and mouse hepatoma Hepa-1 cell lines. In most instances constitutive and inducible CAT activities in the transient CAT expression assay were similar (within 3-fold) to those in the stable transformation CAT assay (selection of G418-resistant colonies following co-transfection with pSV2-neo). In the case of Ha-MSV-containing constructs stably integrated in the two human breast cancer lines, however, CAT expression was more than two orders of magnitude greater than that transiently expressed in these cells. Since the major difference between these two assays is plasmid copy number, these data suggest the presence of limiting amounts of tissue-specific positive-control enhancer-binding factor(s) in the breast carcinoma cell lines. 相似文献
5.
6.
Zheng W Brake PB Bhattacharyya KK Zhang L Zhao D Jefcoate CR 《Archives of biochemistry and biophysics》2003,416(1):53-67
CYP1B1 is unique among P450 cytochromes in exhibiting inductive responses mediated by both the Ah receptor (AhR) and cAMP. cAMP induction was mediated either by a 189bp far upstream enhancer region (FUER, -5110 to -5298) or by a 230bp AhR-responsive enhancer region (AhER) (-797 to -1026). CYP1B1 luciferase reporters respond selectively to cAMP and TCDD in adrenal Y-1 cells (only cAMP), testis MA10 cells (cAMP>TCDD), and C3H10T1/2 mouse embryo fibroblasts (only TCDD). In Y-1 cells, which lack AhR, cAMP induction is totally dependent on the FUER, including absolute requirements for upstream and downstream halves of this region, and for CREB activity at a CRE sequence located at the 3(')-end. cAMP stimulation of the FUER was remarkably high (27-fold) and equally effective when linked to an HSV-TK promoter, indicating direct cAMP activation of the FUER. Binding of CREB to the essential CRE was demonstrated along with dominant negative effects of functionally impaired mutants. cAMP induction in MA10 cells was partially mediated by the FUER mechanism but was regulated additionally by AhER through AhR activity. MA10 cells also exhibit cAMP-dependent AhR down-regulation and AhR/Arnt complex formation. Mutations in AhER including XRE5 were similarly inhibitory to cAMP stimulation in MA10 cells and to TCDD stimulation in C3H10T1/2 cells. Transfection of AhR into the AhR-deficient Y-1 cells did not introduce this second mechanism, which indicated a need for additional components that are present in MA10 cells. 相似文献
7.
8.
9.
10.
11.
12.
13.
14.
15.
Alignment maps and homology analysis of the J-C intron in human, mouse, and rabbit immunoglobulin kappa gene 总被引:3,自引:0,他引:3
The statistically significant shared oligonucleotides (block identities) of
the intervening region (J5-C) in the human, mouse, and rabbit
immunoglobulin (Ig)-kappa gene were determined. These identities maintain
their order (do not cross) and never connect with any Ig-kappa segment
external to the intron region. The two regions of pronounced similarity are
(1) the vicinity of the established enhancer element (Queen and Baltimore
1983) and (2) a 200-bp region approximately 1 kb upstream that we have
labeled the second enhancer element. Similarity is strong between the human
and mouse sequences in the neighborhood of the first enhancer element and
more pronounced between the human and rabbit sequences in the vicinity of
the second enhancer region. The overall extent of similarity between the
mouse and rabbit sequences is less than that between the human and mouse
sequences and that between the human and rabbit sequences. All close and
large dyad-symmetry pairings were ascertained and their possible relations
to the enhancer elements discussed.
相似文献
16.
17.
18.
Transcriptional control of the mouse prealbumin (transthyretin) gene: both promoter sequences and a distinct enhancer are cell specific. 总被引:36,自引:16,他引:20
下载免费PDF全文
![点击此处可从《Molecular and cellular biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The mouse genomic clone for the prealbumin (transthyretin) gene was cloned, and its upstream regulatory regions were analyzed. The 200 nucleotides 5' to the cap site when placed within a recombinant plasmid were sufficient to direct transient expression in HepG2 (human hepatoma) cells, but this DNA region did not support expression in HeLa cells. The sequence of the 200-nucleotide region is highly conserved between mouse and human DNA and can be considered a cell-specific promoter. Deletions of this promoter region identified a crucial element for cell-specific expression between 151 and 110 nucleotides 5' to the RNA start site. A region situated at about 1.6 to 2.15 kilobases upstream of the RNA start site was found to stimulate expression 10-fold in HepG2 cells but not in HeLa cells. This far upstream element was invertible and increased expression from the beta-globin promoter in HepG2 cells. Unlike the simian virus 40 enhancer, the prealbumin enhancer would not stimulate beta-globin synthesis in HeLa cells, and even the simian virus 40 enhancer did not stimulate the prealbumin promoter in HeLa cells. Thus, we identified in the prealbumin gene two DNA elements that respond in a cell-specific manner: a proximal promoter including a crucial sequence between -108 and -151 nucleotides and a distant enhancer element located between 1.6 and 2.15 kilobases upstream. 相似文献
19.
Espéret C Sabatier S Deville MA Ouazana R Bouhassira EE Godet J Morlé F Bernet A 《The Journal of biological chemistry》2000,275(33):25831-25839