A Single Mammalian Mitochondrial Translation Initiation Factor Functionally Replaces Two Bacterial Factors

Overview

Journal Mol Cell

Publisher Cell Press

Specialty Cell Biology

Date 2008 Feb 5

PMID 18243113

Citations 50

Authors

Rahul Gaur

Domenick Grasso

Partha P Datta

P D V Krishna

Gautam Das

Angela Spencer

Rajendra K Agrawal

Linda Spremulli

Umesh Varshney

Affiliations

Soon will be listed here.

Abstract

The mechanism of translation in eubacteria and organelles is thought to be similar. In eubacteria, the three initiation factors IF1, IF2, and IF3 are vital. Although the homologs of IF2 and IF3 are found in mammalian mitochondria, an IF1 homolog has never been detected. Here, we show that bovine mitochondrial IF2 (IF2(mt)) complements E. coli containing a deletion of the IF2 gene (E. coli DeltainfB). We find that IF1 is no longer essential in an IF2(mt)-supported E. coli DeltainfB strain. Furthermore, biochemical and molecular modeling data show that a conserved insertion of 37 amino acids in the IF2(mt) substitutes for the function of IF1. Deletion of this insertion from IF2(mt) supports E. coli for the essential function of IF2. However, in this background, IF1 remains essential. These observations provide strong evidence that a single factor (IF2(mt)) in mammalian mitochondria performs the functions of two eubacterial factors, IF1 and IF2.

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