A single mutation in human mitochondrial DNA polymerase Pol γA affects both polymerization and proofreading activities of only the holoenzyme

Young Sam Lee, Kenneth A. Johnson, Ian J. Molineux, Yuhui Yin

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

Common causes of human mitochondrial diseases are mutations affecting DNA polymerase (Pol) γ, the sole polymerase responsible for DNA synthesis in mitochondria. Although the polymerase and exonuclease active sites are located on the catalytic subunit Pol γA, in holoenzyme both activities are regulated by the accessory subunit Pol γB. Several patients with severe neurological and muscular disorders were reported to carry the Pol γA substitutions R232G or R232H, which lie outside of either active site. We report that Arg232 substitutions have no effect on independent Pol γA activities but show major defects in the Pol γA-Pol γB holoenzyme, including decreased polymerase and increased exonuclease activities, the latter with decreased selectivity for mismatches. We show that Pol γB facilitates distinguishing mismatched from base-paired primer termini and that Pol γA Arg232 is essential for mediating this regulatory function of the accessory subunit. This study provides a molecular basis for the disease symptoms exhibited by patients carrying those substitutions.

Original languageEnglish (US)
Pages (from-to)28105-28116
Number of pages12
JournalJournal of Biological Chemistry
Volume285
Issue number36
DOIs
StatePublished - Sep 3 2010
Externally publishedYes

Fingerprint

Holoenzymes
DNA-Directed DNA Polymerase
Mitochondrial DNA
Polymerization
Catalytic Domain
Exonucleases
Substitution reactions
Accessories
Mutation
Mitochondrial Diseases
Mitochondria
Nervous System Diseases
Defects

ASJC Scopus subject areas

  • Molecular Biology
  • Biochemistry
  • Cell Biology
  • Medicine(all)

Cite this

A single mutation in human mitochondrial DNA polymerase Pol γA affects both polymerization and proofreading activities of only the holoenzyme. / Lee, Young Sam; Johnson, Kenneth A.; Molineux, Ian J.; Yin, Yuhui.

In: Journal of Biological Chemistry, Vol. 285, No. 36, 03.09.2010, p. 28105-28116.

Research output: Contribution to journalArticle

@article{8105a77df55c41568f3c85feb39e97ed,
title = "A single mutation in human mitochondrial DNA polymerase Pol γA affects both polymerization and proofreading activities of only the holoenzyme",
abstract = "Common causes of human mitochondrial diseases are mutations affecting DNA polymerase (Pol) γ, the sole polymerase responsible for DNA synthesis in mitochondria. Although the polymerase and exonuclease active sites are located on the catalytic subunit Pol γA, in holoenzyme both activities are regulated by the accessory subunit Pol γB. Several patients with severe neurological and muscular disorders were reported to carry the Pol γA substitutions R232G or R232H, which lie outside of either active site. We report that Arg232 substitutions have no effect on independent Pol γA activities but show major defects in the Pol γA-Pol γB holoenzyme, including decreased polymerase and increased exonuclease activities, the latter with decreased selectivity for mismatches. We show that Pol γB facilitates distinguishing mismatched from base-paired primer termini and that Pol γA Arg232 is essential for mediating this regulatory function of the accessory subunit. This study provides a molecular basis for the disease symptoms exhibited by patients carrying those substitutions.",
author = "Lee, {Young Sam} and Johnson, {Kenneth A.} and Molineux, {Ian J.} and Yuhui Yin",
year = "2010",
month = "9",
day = "3",
doi = "10.1074/jbc.M110.122283",
language = "English (US)",
volume = "285",
pages = "28105--28116",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "36",

}

TY - JOUR

T1 - A single mutation in human mitochondrial DNA polymerase Pol γA affects both polymerization and proofreading activities of only the holoenzyme

AU - Lee, Young Sam

AU - Johnson, Kenneth A.

AU - Molineux, Ian J.

AU - Yin, Yuhui

PY - 2010/9/3

Y1 - 2010/9/3

N2 - Common causes of human mitochondrial diseases are mutations affecting DNA polymerase (Pol) γ, the sole polymerase responsible for DNA synthesis in mitochondria. Although the polymerase and exonuclease active sites are located on the catalytic subunit Pol γA, in holoenzyme both activities are regulated by the accessory subunit Pol γB. Several patients with severe neurological and muscular disorders were reported to carry the Pol γA substitutions R232G or R232H, which lie outside of either active site. We report that Arg232 substitutions have no effect on independent Pol γA activities but show major defects in the Pol γA-Pol γB holoenzyme, including decreased polymerase and increased exonuclease activities, the latter with decreased selectivity for mismatches. We show that Pol γB facilitates distinguishing mismatched from base-paired primer termini and that Pol γA Arg232 is essential for mediating this regulatory function of the accessory subunit. This study provides a molecular basis for the disease symptoms exhibited by patients carrying those substitutions.

AB - Common causes of human mitochondrial diseases are mutations affecting DNA polymerase (Pol) γ, the sole polymerase responsible for DNA synthesis in mitochondria. Although the polymerase and exonuclease active sites are located on the catalytic subunit Pol γA, in holoenzyme both activities are regulated by the accessory subunit Pol γB. Several patients with severe neurological and muscular disorders were reported to carry the Pol γA substitutions R232G or R232H, which lie outside of either active site. We report that Arg232 substitutions have no effect on independent Pol γA activities but show major defects in the Pol γA-Pol γB holoenzyme, including decreased polymerase and increased exonuclease activities, the latter with decreased selectivity for mismatches. We show that Pol γB facilitates distinguishing mismatched from base-paired primer termini and that Pol γA Arg232 is essential for mediating this regulatory function of the accessory subunit. This study provides a molecular basis for the disease symptoms exhibited by patients carrying those substitutions.

UR - http://www.scopus.com/inward/record.url?scp=77956245940&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77956245940&partnerID=8YFLogxK

U2 - 10.1074/jbc.M110.122283

DO - 10.1074/jbc.M110.122283

M3 - Article

VL - 285

SP - 28105

EP - 28116

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 36

ER -