Current Genetics

, Volume 32, Issue 3, pp 163–174

A novel nuclear gene, CBT1, essential for mitochondrial cytochrome b formation: terminal processing of mRNA and intron dependence

  • K.-J. Rieger
  • G. Aljinovic
  • Jaga Lazowska
  • Thomas M. Pohl
  • Piotr P. Slonimski
ORIGINAL PAPER

DOI: 10.1007/s002940050262

Cite this article as:
Rieger, KJ., Aljinovic, G., Lazowska, J. et al. Curr Genet (1997) 32: 163. doi:10.1007/s002940050262

Abstract

We describe a new nuclear gene, CBT1 (Cytochrome B Termination), specifically involved in the generation of mature mRNA of cytochrome b in yeast mitochondria. Disruption of CBT1 (corresponding to ORF YKL 208W) results in a respiratory deficiency (no growth on acetate and ethanol, a reduced growth on glycerol, and a moderate growth on lactate). Cytochrome b is practically undetectable spectrally, while cytochromes a and a3 (cytochrome oxidase) appear unaffected by the disruption. Analysis of mitochondrial transcripts shows a reduced abundance of cytb mRNA, which in addition is approximately 200 nucleotides longer than that of the wild-type. Sequencing of the 3′ region of the mutant cytb mRNA with an oligonucleotide primer positioned 148 nt downstream from the dodecamer sequence (``end-of-messenger'' signal), demonstrates that the mutant transcript is extended beyond this position and is not processed at the conserved dodecamer cleavage site. The CBT1 gene product may be one of the components required for the exact 3′ cleavage of the cytb messenger and may also be related to RNA splicing, since the intron-containing cytb gene is not as well expressed as the intron-less gene and the respiratory deficiency is more severe. We propose, that the CBT1 protein is necessary for the correct trimming of the end of cytb pre-mRNA and may be a part of the multi-component complex involved in this process.

Key wordsSaccharomyces cerevisiaeNucleo-mitochondrial interactionCytochrome bmRNA processingYKL 208W

Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • K.-J. Rieger
    • 1
  • G. Aljinovic
    • 2
  • Jaga Lazowska
    • 1
  • Thomas M. Pohl
    • 2
  • Piotr P. Slonimski
    • 1
  1. 1.Centre de Génétique Moleculaire, Laboratoire propre du CNRS associéà l'Université P. et M. Curie, F-91198 Gif-sur-Yvette cedex, FranceFR
  2. 2.GATC GmbH, Fritz-Arnold-Strasse 23, D-78467 Konstanz, GermanyDE