Open AccessDifferential expression of oocyte-type class III genes with fraction TFIIIC from immature or mature oocytes.
Author(s) -
Wanda F. Reynolds,
Deborah L. Johnson
Publication year - 1992
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.12.3.946
Subject(s) - biology , oocyte , xenopus , gene , somatic cell , gene expression , transcription (linguistics) , microbiology and biotechnology , transcription factor , genetics , embryo , linguistics , philosophy
The Xenopus OAX genes can be expressed in oocytes but are virtually inactive in somatic tissues. The tRNA(Met1) (tMET) genes also appear to be developmentally regulated. We have examined the reason for the differential expression of these class III genes. Analysis of the transcriptional activities of extracts derived from immature and mature oocytes revealed that the developmental regulation of these genes can be reproduced in vitro. We have partially purified the required transcription factors B and C from these extracts to ascertain the components responsible for this differential activity. The immature oocyte C fraction activates the tMET and OAX genes when reconstituted with either the immature or mature oocyte-derived B fraction. In contrast, the mature oocyte C fraction fails to activate these genes regardless of which B fraction is used. Both C fractions activated the somatic 5S gene. Purification of the oocyte C fractions by phosphocellulose or B box DNA affinity chromatography failed to separate additional activities responsible for the differential expression of OAX or tMET. By using template exclusion assays, the inability of the mature oocyte C fraction to activate transcription was correlated with an inability to form stable transcription complexes with the tMET or OAX gene.