Transcription complexes that program Xenopus 5S RNA genes are stable in vivo.
The long-term stability of transcription complexes on 5S RNA genes has been demonstrated in vivo. Complexes on oocyte and somatic-type 5S RNA genes injected into Xenopus laevis oocyte nuclei are stable for at least 4 days. Tissue culture cells and mature erythrocytes have equivalent numbers of somatic 5S RNA genes programmed into transcription complexes, yet the former cell type has a greater than 50-fold higher cellular content of transcription factor IIIA (TFIIIA). Functional transcription complexes on somatic 5S RNA genes in nucleated erythrocytes of Xenopus are stable for weeks, perhaps months, even though a mature erythrocyte has less than two molecules of TFIIIA for each somatic 5S RNA gene. These findings strengthen our proposal that stable transcription complexes are a means of maintaining the differentiated state.
Darby
M K
MK
Department of Embryology, Carnegie Institution of Washington, Baltimore, MD 21210.
Andrews
M T
MT
Brown
D D
DD
D000818:Animals; D002467:Cell Nucleus / Q000502:physiology; D002478:Cells, Cultured; D002843:Chromatin / Q000502:physiology; D004247:DNA / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D004912:Erythrocytes / Q000502:physiology; D009693:Nucleic Acid Hybridization; D009865:Oocytes / Q000502:physiology / Q000648:ultrastructure; D012335:RNA, Ribosomal / Q000235:genetics*; D012341:RNA, Ribosomal, 5S / Q000235:genetics*; D035582:Transcription Factor TFIIIA; D014157:Transcription Factors / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D014158:Transcription, Genetic; D014982:Xenopus laevis / Q000235:genetics*
D002843:Chromatin; D012335:RNA, Ribosomal; D012341:RNA, Ribosomal, 5S; D035582:Transcription Factor TFIIIA; D014157:Transcription Factors; D004247:DNA