共查询到20条相似文献,搜索用时 13 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
Nuclear factors that bind to the enhancer region of nondefective Friend murine leukemia virus. 总被引:2,自引:12,他引:2 下载免费PDF全文
Nondefective Friend murine leukemia virus (MuLV) causes erythroleukemia when injected into newborn NFS mice, while Moloney MuLV causes T-cell lymphoma. Exchange of the Friend virus enhancer region, a sequence of about 180 nucleotides including the direct repeat and a short 3'-adjacent segment, for the corresponding region in Moloney MuLV confers the ability to cause erythroid disease on Moloney MuLV. We have used the electrophoretic mobility shift assay and methylation interference analysis to identify cellular factors which bind to the Friend virus enhancer region and compared these with factors, previously identified, that bind to the Moloney virus direct repeat (N. A. Speck and D. Baltimore, Mol. Cell. Biol. 7:1101-1110, 1987). We identified five binding sites for sequence-specific DNA-binding proteins in the Friend virus enhancer region. While some binding sites are present in both the Moloney and Friend virus enhancers, both viruses contain unique sites not present in the other. Although none of the factors identified in this report which bind to these unique sites are present exclusively in T cells or erythroid cells, they bind to three regions of the enhancer shown by genetic analysis to encode disease specificity and thus are candidates to mediate the tissue-specific expression and distinct disease specificities encoded by these virus enhancer elements. 相似文献
14.
15.
16.
17.
18.
Nuclear factors specifically bind to upstream sequences of a Xenopus laevis ribosomal protein gene promoter. 总被引:3,自引:1,他引:3 下载免费PDF全文
The upstream region of the Xenopus laevis L14 ribosomal protein gene was deleted starting from the 5' extremity in order to define the promoter length necessary to express a linked reporter CAT gene. The functional analysis indicated that a sequence located between -63 and -49 from the capsite is important for an efficient promoter activity. Band shift and ExoIII protection assays evidenced the binding to this region of a factor, called XrpFI, present in the crude nuclear extract from X.laevis oocytes. Methylation interference analysis localized the contacts in the G residues belonging to a short box, 5' CTTCC 3', positioned between -53 and -49 from the capsite. An additional factor, XrpFII, makes contacts with the sequence 5'GCCTGTTCGCC 3' located between -27 and -17 from the capsite. The deletion mutant still containing this sequence is poorly transcribed, but resumes activity when a short fragment containing the binding site for factor XrpFI is cloned in an upstream position. 相似文献
19.
20.
Multiple basal promoter elements determine the level of human c-fos transcription. 总被引:7,自引:2,他引:5 下载免费PDF全文
L Runkel P E Shaw R E Herrera R A Hipskind A Nordheim 《Molecular and cellular biology》1991,11(3):1270-1280