共查询到20条相似文献,搜索用时 15 毫秒
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Differential binding of zinc fingers from Xenopus TFIIIA and p43 to 5S RNA and the 5S RNA gene. 下载免费PDF全文
Zinc fingers are usually associated with proteins that interact with DNA. Yet in two oocyte-specific Xenopus proteins, TFIIA and p43, zinc fingers are used to bind 5S RNA. One of these, TFIIIA, also binds the 5S RNA gene. Both proteins have nine zinc fingers that are nearly identical with respect to size and spacing. We have determined the relative affinities of groups of zinc fingers from TFIIIA for both 5S RNA and the 5S RNA gene. We have also determined the relative affinities of groups of zinc fingers from p43 for 5S RNA. The primary protein regions for RNA and DNA interaction in TFIIIA are located at opposite ends of the molecule. All zinc fingers from TFIIIA participate in binding 5S RNA, but zinc fingers from the C terminus have the highest affinity. N-terminal zinc fingers are essential for binding the 5S RNA gene. In contrast, zinc fingers at the amino terminus of p43 are essential for binding 5S RNA. 相似文献
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Mutations in 5S DNA and 5S RNA have different effects on the binding of Xenopus transcription factor IIIA 总被引:6,自引:0,他引:6
The effects on TFIIIA binding affinity of a series of substitution mutations in the Xenopus laevis oocyte 5S RNA gene were quantified. These data indicate that TFIIIA binds specifically to 5S DNA by forming sequence-specific contacts with three discrete sites located within the classical A and C boxes and the intermediate element of the internal control region. Substitution of the nucleotide sequence at any of the three sites significantly reduces TFIIIA binding affinity, with a 100-fold reduction observed for substitutions in the box C subregion. These results are consistent with a direct interaction of TFIIIA with specific base pairs within the major groove of the DNA. A comparison of the TFIIIA binding data for the same mutations expressed in 5S RNA indicates that the protein does not make any strong sequence-specific contacts with the RNA. Although the protein footprinting sites on the 5S DNA and 5S RNA are coincident, nucleotide substitutions in 5S RNA which moderately reduce TFIIIA binding affinity do not correspond at all to the three specific TFIIIA interaction sites within the gene. The implications of these results for models which attempt to reconcile the DNA and RNA binding activities of TFIIIA by proposing a common structural motif for the two nucleic acids are discussed. 相似文献
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J S Hanas D J Hazuda D F Bogenhagen F Y Wu C W Wu 《The Journal of biological chemistry》1983,258(23):14120-14125
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Transcription fraction TFIIIC can regulate differential Xenopus 5S RNA gene transcription in vitro 总被引:30,自引:4,他引:26 下载免费PDF全文
A P Wolffe 《The EMBO journal》1988,7(4):1071-1079
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RNA and DNA binding zinc fingers in Xenopus TFIIIA. 总被引:4,自引:0,他引:4
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Characterization of the equilibrium binding of Xenopus transcription factor IIIA to the 5 S RNA gene 总被引:3,自引:0,他引:3
P J Romaniuk 《The Journal of biological chemistry》1990,265(29):17593-17600
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Oocyte and somatic 5S ribosomal RNA and 5S RNA encoding genes in Xenopus tropicalis. 总被引:2,自引:2,他引:0
W Nietfeld M Digweed H Mentzel W Meyerhof M K?ster W Kn?chel V A Erdmann T Pieler 《Nucleic acids research》1988,16(18):8803-8815
We have investigated the structure of oocyte and somatic 5S ribosomal RNA and of 5S RNA encoding genes in Xenopus tropicalis. The sequences of the two 5S RNA families differ in four positions, but only one of these substitutions, a C to U transition in position 79 within the internal control region of the corresponding 5S RNA encoding genes, is a distinguishing characteristic of all Xenopus somatic and oocyte 5S RNAs characterized to date, including those from Xenopus laevis and Xenopus borealis. 5S RNA genes in Xenopus tropicalis are organized in clusters of multiple repeats of a 264 base pair unit; the structural and functional organization of the Xenopus tropicalis oocyte 5S gene is similar to the somatic but distinct from the oocyte 5S DNA in Xenopus laevis and Xenopus borealis. A comparative sequence analysis reveals the presence of a strictly conserved pentamer motif AAAGT in the 5'-flanking region of Xenopus 5S genes which we demonstrate in a separate communication to serve as a binding signal for an upstream stimulatory factor. 相似文献
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A quantitative assay for Xenopus 5S RNA gene transcription in vitro 总被引:37,自引:0,他引:37
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