A Chinese Hamster Mutant Cell Line with a Defect in the Integral Membrane Protein CII-3 of Complex II of the Mitochondrial Electron Transport Chain

Frank G Oostveen,Harry C Au,Per-Johan Meijer,Immo E Scheffler

doi:10.1074/jbc.270.44.26104

Abstract

In this study, a respiration-deficient Chinese hamster cell line with a defect in succinate dehydrogenase activity is shown to result from a single base change in a codon in the coding sequence for the membrane anchor protein CII-3 (also referred to as QPs-1). A premature translation stop results in the truncation of 33 amino acids from the C terminus. Bovine cDNA encoding this peptide complements the mutation. There is about 82% identity between these two mammalian proteins. The gene for CII-3 was mapped on human chromosome 1, and because it is also found on minichromosomes characterized by our laboratory, we can localize it on the short arm within 1-2 megabases from the centromere.

Highlights

A series of respiration-deficient Chinese hamster cell mutants isolated by our laboratory can grow normally in tissue culture as long as an adequate supply of glucose is available for glycolysis [1,2,3]
The gene for CII-3 was mapped on human chromosome 1, and because it is found on minichromosomes characterized by our laboratory, we can localize it on the short arm within 1–2 megabases from the centromere
Southern Analysis of Human, Hamster, and Hybrid Genomic DNA with the CII-3 cDNA Probe—Bovine CII-3 cDNA was used as a probe in Southern analyses with genomic DNA from hamster and human cell lines and from various human-hamster hybrids

Summary

Introduction

A series of respiration-deficient Chinese hamster cell mutants isolated by our laboratory can grow normally in tissue culture as long as an adequate supply of glucose is available for glycolysis [1,2,3]. The mutants were grouped into seven complementation groups by somatic cell fusions [1], and one, represented by mutant CCL16-B9, was characterized to be almost completely deficient in succinate dehydrogenase activity (SDH)1 [4, 5] This enzyme, which links the reactions of the Krebs cycle to the electron transport chain, is part of a complex of four polypeptides (complex II) in the inner mitochondrial membrane. The precursor polypeptides are synthesized in the cytosol and subsequently or concurrently imported into mitochondria Following processing to their mature forms, the biogenesis of a functional complex II requires covalent attachment of flavin to the largest subunit (Fp) [10], formation of the three non-heme iron-sulfur clusters in the Ip subunit, and assembly of the heme with the membrane anchor proteins. CDNAs were cloned by RT-PCR from both wild type and mutant hamster cell lines, and the sequence comparison shows that a single base substitution in the mutant creates a premature stop codon

Methods

Results

Conclusion