期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1991
卷号：88
期号：9
页码：3962-3966
DOI：10.1073/pnas.88.9.3962
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The 35S rRNA gene of the yeast Saccharomyces cerevisiae was fused to the GAL7 promoter. This hybrid gene, when present on a multicopy plasmid and induced by galactose, suppressed the growth defects of a temperature-sensitive RNA polymerase I (pol I) mutant and those of a mutant in which the gene for the second largest subunit of pol I was deleted. Analysis of pulse-labeled RNA directly demonstrated that rRNA synthesis in this deletion mutant is from the GAL7 promoter. These experiments show that the sole essential function of pol I is the transcription of the rRNA genes, that pol I is not absolutely required for the synthesis of rRNA and ribosomes or cell growth if 35S rRNA synthesis is achieved by some other means, and that the tandemly repeated structure of the chromosomal rRNA genes is also not absolutely required for the synthesis of rRNA and ribosomes.
