The C-terminal domain of transcription factor IIIA interacts differently with different 5S RNA genes.
DNase I footprints and affinity measurements showed that the C-terminal arm of Xenopus transcription factor IIIA interacts differently with different Xenopus 5S DNAs, forming three distinct types of transcription factor IIIA-5S DNA complexes: a somatic type, a major-oocyte (and pseudogene) type, and a trace-oocyte type. Site-directed mutagenesis on the major-oocyte 5S gene revealed that somatic-type changes at positions 53, 55, and 56 changed the structure of the transcription factor IIIA-5S DNA complex from major-oocyte to somatic, and a single trace-oocyte change at position 56 caused the change from major-oocyte to trace-oocyte complex. We further show that the somatic-type changes are accompanied by a marked enhancement in the rate of 5S RNA transcription, and we discuss the possible biological relevance of these findings.
Xing
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Department of Biology, University of Rochester, New York 14627.
Worcel
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D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D003850:Deoxyribonuclease I; D005260:Female; D008969:Molecular Sequence Data; D009154:Mutation; D009865:Oocytes / Q000378:metabolism; D010957:Plasmids; D012335:RNA, Ribosomal / Q000235:genetics*; D012341:RNA, Ribosomal, 5S / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D035582:Transcription Factor TFIIIA; D014157:Transcription Factors / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D014158:Transcription, Genetic; D014982:Xenopus laevis
D012335:RNA, Ribosomal; D012341:RNA, Ribosomal, 5S; D035582:Transcription Factor TFIIIA; D014157:Transcription Factors; D003850:Deoxyribonuclease I