Current Genetics

, Volume 34, Issue 6, pp 449–458

In vivo mitochondrial DNA-protein interactions in sea urchin eggs and embryos

  • Marina Roberti
  • Paola Loguercio Polosa
  • Clara Musicco
  • Francesco Milella
  • Sohail A. Qureshi
  • Maria N. Gadaleta
  • Howard T. Jacobs
  • P. Cantatore
ORIGINAL PAPER

DOI: 10.1007/s002940050419

Cite this article as:
Roberti, M., Loguercio Polosa, P., Musicco, C. et al. Curr Genet (1999) 34: 449. doi:10.1007/s002940050419

Abstract

Footprinting studies with the purine-modifying agent dimethyl sulphate were performed in Paracentrotus lividus eggs and embryos to analyze in vivo the interactions between protein and mitochondrial DNA. Footprinting in the small non-coding region and at the boundary between the ND5 and ND6 genes revealed two strong contact sites corresponding with the in vitro binding sequences of mitochondrial D-loop-Binding Protein (mtDBP). The analysis of the pause region of mtDNA replication showed a strong footprint corresponding with the binding site of the mitochondrial Pause region-Binding Protein-2 (mtPBP-2), but only a very weak signal at the binding site of the mitochondrial Pause region-Binding Protein-1 (mtPBP-1), which in vitro binds DNA with high efficiency. In vitro and in vivo analysis of the 3′ end-region of the two rRNA genes showed no significant protein-DNA interactions, suggesting that, in contrast to mammals, the 3′ ends of sea urchin mitochondrial rRNAs are not generated by a protein-dependent transcription termination event. These and other data support a model in which expression of mitochondrial genes in sea urchins is regulated post-transcriptionally. Footprinting at the five AT-rich consensus regions allowed the detection of a binding site in the non-coding region for an as-yet unidentified protein, mtAT-1BP. The occupancy of this site appears to be developmentally regulated, being detectable in the pluteus larval stage, but not in unfertilized eggs.

Key words Sea urchinmtDNADMS footprintingDNA-binding proteins

Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • Marina Roberti
    • 1
  • Paola Loguercio Polosa
    • 1
  • Clara Musicco
    • 1
  • Francesco Milella
    • 1
  • Sohail A. Qureshi
    • 2
  • Maria N. Gadaleta
    • 1
  • Howard T. Jacobs
    • 2
  • P. Cantatore
    • 1
  1. 1.Dipartimento di Biochimica e Biologia Molecolare, Università di Bari and Centro Studi sui Mitocondri e Metabolismo Energetico, CNR, via Orabona 4A, I-70125, Bari, Italy e-mail: csmmal05@area.ba.cnr.it Tel.: +39-80-5443378 Fax: +39-80-5443317IT
  2. 2.Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, UKGB
  3. 3.Institute of Medical Technology and Tampere University Hospital, University of Tampere, P. O. Box 607, 33101 Tampere, FinlandFI