The role of DNA-mediated transfer of TFIIIA in the concerted gyration and differential activation of the Xenopus 5S RNA genes.
The transcription factor of the 5S RNA gene, TFIIIA, induces gyration of oocyte- and somatic-type 5S DNA plasmids in Xenopus oocyte extracts, but oocyte 5S gyration requires a 5-fold higher TFIIIA concentration than somatic 5S gyration. Concomitant with the differential gyration at intermediate TFIIIA concentrations, the oocyte genes are repressed and the somatic genes become activated, a situation that mimics the one seen in Xenopus somatic cells. Data obtained with plasmids immobilized in agarose indicate that TFIIIA finds its site via a DNA-mediated transfer mechanism, and that all-or-none gyration is a consequence of TFIIIA transfer between 5S DNA sites. Based on these results, we present a model that explains the differential all-or-none activation of the 5S RNA genes.
Kmiec
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Razvi
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D000818:Animals; D002843:Chromatin / Q000648:ultrastructure; D004247:DNA / Q000235:genetics*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005786:Gene Expression Regulation; D008957:Models, Genetic; D009690:Nucleic Acid Conformation; D009865:Oocytes; D010957:Plasmids; D012335:RNA, Ribosomal / Q000235:genetics*; D035582:Transcription Factor TFIIIA; D014157:Transcription Factors / Q000235:genetics* / Q000502:physiology; D014158:Transcription, Genetic; D014982:Xenopus laevis / Q000235:genetics* / Q000378:metabolism
D002843:Chromatin; D012335:RNA, Ribosomal; D035582:Transcription Factor TFIIIA; D014157:Transcription Factors; D004247:DNA