Function of basonuclin in increasing transcription of the ribosomal RNA genes during mouse oogenesis.
Active protein synthesis during early oogenesis requires accelerated transcription of ribosomal RNA genes (rDNAs). In response to this demand, rDNAs are amplified more than 1000-fold early in Xenopus oogenesis. Here, we report evidence that rDNA is not amplified in mouse oocytes, but these cells may instead employ the zinc-finger protein basonuclin, a putative rDNA transcription factor, to enhance rRNA synthesis. This conclusion is based on observations that basonuclin is localized in the nucleolus in the mouse oocyte early in its growth phase, when rRNA transcription is highly active; and that the binding sites of basonuclin zinc fingers on the human and mouse rDNA promoters are homologous. In a co-transfection assay, basonuclin can elevate transcription from an rDNA promoter, and its zinc-finger domain can inhibit RNA polymerase I transcription, as detected by a run-on assay, in growing mouse oocytes.
Tian
Q
Q
Department of Dermatology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
Kopf
G S
GS
Brown
R S
RS
Tseng
H
H
D000818:Animals; D001665:Binding Sites; D002466:Cell Nucleolus / Q000737:chemistry / Q000235:genetics; D018983:DNA Footprinting; D004275:DNA, Ribosomal / Q000032:analysis / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005260:Female; D005784:Gene Amplification; D018628:Gene Dosage; D005786:Gene Expression Regulation; D020459:Genes, rRNA / Q000235:genetics*; D007150:Immunohistochemistry; D051379:Mice; D008815:Mice, Inbred Strains; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D009865:Oocytes / Q000378:metabolism; D009866:Oogenesis / Q000235:genetics*; D010750:Phosphoproteins; D011401:Promoter Regions, Genetic / Q000235:genetics; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012318:RNA Polymerase I / Q000037:antagonists & inhibitors / Q000378:metabolism; D012335:RNA, Ribosomal / Q000096:biosynthesis* / Q000235:genetics; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection; D016335:Zinc Fingers
C511595:Bnc1 protein, mouse; D004275:DNA, Ribosomal; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011506:Proteins; D012335:RNA, Ribosomal; C088179:RNA, ribosomal, 45S; D014157:Transcription Factors; D012318:RNA Polymerase I