The C-terminal tail of mitochondrial transcription factor A markedly strengthens its general binding to DNA

Kippei Ohgaki, Tomotake Kanki, Atsushi Fukuoh, Hironori Kurisaki, Yoshimasa Aoki, Masaki Ikeuchi, Ho Kim Sang, Naotaka Hamasaki, Dongchon Kang

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

Mitochondrial transcription factor A (TFAM) contains a basic C-terminal tail which is essential for the promoter-specific transcription. TFAM is also a major component of a protein-mitochondrial DNA (mtDNA) complex, called nucleoid, as a non-specific DNA-binding protein. However, little is known about a role of the C-tail in the nucleoid. Overexpression of full-length TFAM decreased the amount of a D-loop form of mtDNA in cells, while overexpression of TFAM lacking its C-tail (TFAM-ΔC) did not, suggesting that the C-tail is involved in destabilization or formation of the D-loop. An mRNA for mtDNA-derived ND1 was hardly decreased in the former but rather decreased in the latter. Given that the D-loop formation is coupled with the transcription, the decrease in the D-loop is likely due to its destabilization. The recombinant full-length TFAM much strongly unwound DNA than TFAM-ΔC, which is consistent with the above idea because D-loop is resolved by unwinding of the supercoiling state. Notably, truncation of the C-tail decreased DNA-binding activity of TFAM by three orders of magnitude. Thus, the C-terminal tail of TFAM is important for the strong general binding to mtDNA. This strong DNA-binding conferred by the C-tail may play an important role in the nucleoid structure.

Original languageEnglish
Pages (from-to)201-211
Number of pages11
JournalJournal of biochemistry
Volume141
Issue number2
DOIs
Publication statusPublished - Feb 1 2007

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology

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