TY - JOUR
T1 - In organello formaldehyde crosslinking of proteins to mtDNA
T2 - Identification of bifunctional proteins
AU - Kaufman, Brett A.
AU - Newman, Scott M.
AU - Hallberg, Richard L.
AU - Slaughter, Clive A.
AU - Perlman, Philip S.
AU - Butow, Ronald A.
PY - 2000/7/5
Y1 - 2000/7/5
N2 - The segregating unit of mtDNA is a protein-DNA complex called the nucleoid. In an effort to understand how nucleoid proteins contribute to mtDNA organization and inheritance, we have developed an in organello formaldehyde crosslinking procedure to identify proteins associated with mtDNA. Using highly purified mitochondria, we observed a time-dependent crosslinking of protein to mtDNA as determined by sedimentation through isopycnic cesium chloride gradients. We detected ≃20 proteins crosslinked to mtDNA and identified 11, mostly by mass spectrometry. Among them is Abf2p, an abundant, high-mobility group protein that is known to function in nucleoid morphology, and in mtDNA transactions. In addition to several other proteins with known DNA binding properties or that function in mtDNA maintenance, we identified other mtDNA-associated proteins that were not anticipated, such as the molecular chaperone Hsp60p and a Krebs cycle protein, Kgd2p. Genetic experiments indicate that hsp60-ts mutants have a petite-inducing phenotype at the permissive temperature and that a kgd2Δ mutation increases the petite-inducing phenotype of an abf2Δ mutation. Crosslinking and DNA gel shift experiments show that Hsp60p binds to single-stranded DNA with high specificity for the template strand of a putative origin of mtDNA replication. These data identify bifunctional proteins that participate in the stability of ρ+ mtDNA.
AB - The segregating unit of mtDNA is a protein-DNA complex called the nucleoid. In an effort to understand how nucleoid proteins contribute to mtDNA organization and inheritance, we have developed an in organello formaldehyde crosslinking procedure to identify proteins associated with mtDNA. Using highly purified mitochondria, we observed a time-dependent crosslinking of protein to mtDNA as determined by sedimentation through isopycnic cesium chloride gradients. We detected ≃20 proteins crosslinked to mtDNA and identified 11, mostly by mass spectrometry. Among them is Abf2p, an abundant, high-mobility group protein that is known to function in nucleoid morphology, and in mtDNA transactions. In addition to several other proteins with known DNA binding properties or that function in mtDNA maintenance, we identified other mtDNA-associated proteins that were not anticipated, such as the molecular chaperone Hsp60p and a Krebs cycle protein, Kgd2p. Genetic experiments indicate that hsp60-ts mutants have a petite-inducing phenotype at the permissive temperature and that a kgd2Δ mutation increases the petite-inducing phenotype of an abf2Δ mutation. Crosslinking and DNA gel shift experiments show that Hsp60p binds to single-stranded DNA with high specificity for the template strand of a putative origin of mtDNA replication. These data identify bifunctional proteins that participate in the stability of ρ+ mtDNA.
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U2 - 10.1073/pnas.140063197
DO - 10.1073/pnas.140063197
M3 - Article
C2 - 10869431
AN - SCOPUS:0034608792
SN - 0027-8424
VL - 97
SP - 7772
EP - 7777
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 14
ER -