Characterization of the Human Mitochondrial Translational Release Factor(s)
Mitochondria, the powerhouses of the cell, possess their own translational system seemingly inherited from their proteo-bacterial ancestor. Termination of translation in bacteria is mediated by Release Factors 1, 2 and 3 (RF1, 2 & 3), the first two of which recognise stop codons UAA, UAG and UGA...
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Tehran University of Medical Sciences
2005-03-01
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doaj-01102c4aedf74d5b9ca88481c683cb582020-12-02T18:55:20ZengTehran University of Medical SciencesIranian Journal of Public Health2251-60852251-60932005-03-0134Supple 1Characterization of the Human Mitochondrial Translational Release Factor(s) HR Soleimanpour0 ZM Chrzanowska-Lightowlers1 RN Lightowlers2 Mitochondria, the powerhouses of the cell, possess their own translational system seemingly inherited from their proteo-bacterial ancestor. Termination of translation in bacteria is mediated by Release Factors 1, 2 and 3 (RF1, 2 & 3), the first two of which recognise stop codons UAA, UAG and UGA, while RF3 just enhances the efficiency of termination. In human mitochondria where translation termination is triggered by four stop codons (UAA, UAG, AGG and AGA), only one candidate gene (MTRF1) is purported in silico to encode a functional mitochondrial release factor. Having searched the human genome database, we have found another candidate (NP_061914) potentially capable of acting as mitochondrial release factor based upon its high similarity to bacterial RF1 and MTRF1. To determine whether these two candidates are located in the mitochondrion, they have been cloned into a GFP expression vector (pGFP3) and transfected into HeLa cells for 48 hours followed by staining with Mitotracker Red CMXRos. Analysis of the cells with Fluorescence Microscopy equipped with Metamorphosis software showed localization of the two GFP chimaeras to mitochondria, implying mitochondrial localization of MTRF1 and “NP_061914”. To determine whether “NP_061914” is actually imported into mitochondria, a radiolabelled product was generated in vitro and incubated with isolated rat liver mitochondria. N-terminal cleavage was demonstrated and the matured protein became insensitive to added proteinase, consistent with “NP_061914” accessing the mitochondrial matrix. This protein has now been renamed “MTRF2”.https://ijph.tums.ac.ir/index.php/ijph/article/view/2998Mitochondrial release factorMitochondrial translationTranslational terminationMitochondrial import |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
HR Soleimanpour ZM Chrzanowska-Lightowlers RN Lightowlers |
spellingShingle |
HR Soleimanpour ZM Chrzanowska-Lightowlers RN Lightowlers Characterization of the Human Mitochondrial Translational Release Factor(s) Iranian Journal of Public Health Mitochondrial release factor Mitochondrial translation Translational termination Mitochondrial import |
author_facet |
HR Soleimanpour ZM Chrzanowska-Lightowlers RN Lightowlers |
author_sort |
HR Soleimanpour |
title |
Characterization of the Human Mitochondrial Translational Release Factor(s) |
title_short |
Characterization of the Human Mitochondrial Translational Release Factor(s) |
title_full |
Characterization of the Human Mitochondrial Translational Release Factor(s) |
title_fullStr |
Characterization of the Human Mitochondrial Translational Release Factor(s) |
title_full_unstemmed |
Characterization of the Human Mitochondrial Translational Release Factor(s) |
title_sort |
characterization of the human mitochondrial translational release factor(s) |
publisher |
Tehran University of Medical Sciences |
series |
Iranian Journal of Public Health |
issn |
2251-6085 2251-6093 |
publishDate |
2005-03-01 |
description |
Mitochondria, the powerhouses of the cell, possess their own translational system seemingly inherited from their proteo-bacterial ancestor. Termination of translation in bacteria is mediated by Release Factors 1, 2 and 3 (RF1, 2 & 3), the first two of which recognise stop codons UAA, UAG and UGA, while RF3 just enhances the efficiency of termination. In human mitochondria where translation termination is triggered by four stop codons (UAA, UAG, AGG and AGA), only one candidate gene (MTRF1) is purported in silico to encode a functional mitochondrial release factor. Having searched the human genome database, we have found another candidate (NP_061914) potentially capable of acting as mitochondrial release factor based upon its high similarity to bacterial RF1 and MTRF1. To determine whether these two candidates are located in the mitochondrion, they have been cloned into a GFP expression vector (pGFP3) and transfected into HeLa cells for 48 hours followed by staining with Mitotracker Red CMXRos. Analysis of the cells with Fluorescence Microscopy equipped with Metamorphosis software showed localization of the two GFP chimaeras to mitochondria, implying mitochondrial localization of MTRF1 and “NP_061914”. To determine whether “NP_061914” is actually imported into mitochondria, a radiolabelled product was generated in vitro and incubated with isolated rat liver mitochondria. N-terminal cleavage was demonstrated and the matured protein became insensitive to added proteinase, consistent with “NP_061914” accessing the mitochondrial matrix. This protein has now been renamed “MTRF2”. |
topic |
Mitochondrial release factor Mitochondrial translation Translational termination Mitochondrial import |
url |
https://ijph.tums.ac.ir/index.php/ijph/article/view/2998 |
work_keys_str_mv |
AT hrsoleimanpour characterizationofthehumanmitochondrialtranslationalreleasefactors AT zmchrzanowskalightowlers characterizationofthehumanmitochondrialtranslationalreleasefactors AT rnlightowlers characterizationofthehumanmitochondrialtranslationalreleasefactors |
_version_ |
1724402479529984000 |