Mapping of transcription initiation and termination signals on Xenopus laevis ribosomal DNA

A. Bakken, G. Morgan, B. Sollner-Webb, J. Roan, S. Busby, R. H. Reeder

Research output: Contribution to journalArticle

Abstract

We have injected cloned derivatives of Xenopus laevis ribosomal genes into X. laevis oocyte nuclei and examined the resulting transcription complexes in the electron microscope. From this work we conclude that the promoter lies somewhere within a region between -320 nucleotides upstream and +113 nucleotides downstream from the site of transcription initiation. This assignment agrees with inferences based on sequence conservation. It further suggests that the duplicated initiation region sequences located further out in the spacer ('Bam islands') are not required for the normal high densities of RNA polymerase loading seen on ribosomal genes. Concerning termination, the cluster of four Ts that forms part of the HindIII restriction site at the 3' end of the gene appears to be part of the normal termination signal. Termination still occurs when only three Ts are present, but reduction to two Ts damages termination. Because clusters of three Ts appear at several sites within the gene, it is likely that sequences adjacent to the T cluster also are required for normal termination. In addition, we present evidence for a fail-safe termination site just upstream from the site of transcription initiation.

Original languageEnglish (US)
Pages (from-to)56-60
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume79
Issue number1
StatePublished - 1982
Externally publishedYes

Fingerprint

Xenopus laevis
Ribosomal DNA
Transcription Initiation Site
Genes
Nucleotides
DNA-Directed RNA Polymerases
Islands
Oocytes
Electrons

ASJC Scopus subject areas

  • Genetics
  • General

Cite this

Mapping of transcription initiation and termination signals on Xenopus laevis ribosomal DNA. / Bakken, A.; Morgan, G.; Sollner-Webb, B.; Roan, J.; Busby, S.; Reeder, R. H.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 79, No. 1, 1982, p. 56-60.

Research output: Contribution to journalArticle

Bakken, A. ; Morgan, G. ; Sollner-Webb, B. ; Roan, J. ; Busby, S. ; Reeder, R. H. / Mapping of transcription initiation and termination signals on Xenopus laevis ribosomal DNA. In: Proceedings of the National Academy of Sciences of the United States of America. 1982 ; Vol. 79, No. 1. pp. 56-60.
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AU - Reeder, R. H.

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