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：1979
卷号：76
期号：8
页码：3957-3961
DOI：10.1073/pnas.76.8.3957
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Untreated Xenopus cells synthesize RNA is increased and some sequences complementary to those of the nontranscribed spacer are found in the heavy shoulder of the 40S precursor rRNA peak. In such events transcription initiation seems to take place within the spacer because its middle and right BamHI endonuclease fragments are preferentially transcribed, whereas only few RNA sequences complementary to the left spacer fragment are found. It is concluded that at least some spacer regions contain promoters for transcription and can be transcribed either into a special class of "spacer transcripts" or into molecules covalently linked to rRNA precursor.
