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Interaction of human mitochondrial transcription factor A in mitochondria: its involvement in the dynamics of mitochondrial DNA nucleoids
Author(s) -
Kasashima Katsumi,
Endo Hitoshi
Publication year - 2015
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1111/gtc.12306
Subject(s) - tfam , mitochondrial dna , biology , mitochondrion , nucleoid , microbiology and biotechnology , transcription factor , mitochondrial fusion , dna , genetics , gene , mitochondrial biogenesis , escherichia coli
Mitochondrial transcription factor A ( TFAM ) is a key regulator of mitochondrial DNA (mt DNA ). TFAM interacts with itself and forms dimers; however, the precise interaction domain in vivo has not yet been determined. We herein showed that human TFAM formed oligomers in mitochondria by in situ chemical cross‐linking. We used the separated fluorescent protein, monomeric Kusabira‐Green, as a reporter to monitor their self‐association in mitochondria. This reporter successfully detected the TFAM – TFAM interaction in cells as fluorescent signals on mitochondria. We also found that the N‐terminal high‐mobility group box domain was sufficient for this interaction. The expression of the dimer‐defective mutant induced enlarged mt DNA nucleoids, suggesting the importance of dimerization in the distribution of mt DNA . The reporter system also supported the association and mixture between independent nucleoids through TFAM by a cell fusion assay using hemagglutinating virus of Japan. We here, for the first time, visualized the interaction of TFAM molecules in mitochondria and proposed its implications for the dynamics of mt DNA nucleoids.