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Identifying the Cox24 Protein as a Factor Involved in Mitochondrial Protein Synthesis
Author(s) -
Shin Jane,
Tibbetts Anne S.,
Appling Dean R.
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.685.2
Subject(s) - biology , mutant , mitochondrial dna , open reading frame , genetics , transfer rna , gene , mutation , rna splicing , protein biosynthesis , translation (biology) , microbiology and biotechnology , rna , messenger rna , peptide sequence
The current understanding of mitochondrial protein synthesis is far from complete; it is likely that many accessory factors required for this process have not yet been identified. The FMT1 gene encodes the S. cerevisiae methionyl‐tRNA formyltransferase, which formylates the mitochondrial initiator Met‐tRNA. A genetic screen was designed to identify accessory factors involved in mitochondrial translation, particularly in the absence of formylated Met‐tRNA. This screen yielded yeast mutants that in combination with the fmt1 deletion, cause dysfunctional mitochondrial respiration. One mutant strain, s.p. 106–1, was transformed with a yeast genomic DNA library to identify open reading frames that complement the synthetic petite phenotype. Library plasmids that complemented the mutation were sequenced and resulting open reading frames were subcloned and expressed in the mutant strain. Expression of the COX24 gene rescued respiratory growth, and sequencing of s.p. 106–1 yeast genomic DNA revealed a T‐to‐C mutation in COX24 that leads to a leucine to proline substitution at amino acid 93. Studies indicate that Cox24p is required for proper splicing of mitochondrial COX1 pre‐mRNA. Our results indicate that Cox24p may also play a role in the initiation of mitochondrial translation, particularly when formylated Met‐tRNA is not available. Work supported by HHMI and NSF grants to the Freshman Research Initiative.