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J B LePecq

Publications and source records attributed to J B LePecq.

6 recordsLinked to original sources
PubMed1997

Isolation and characterization of mitochondrial DNA-less lines from various mammalian cell lines by application of an anticancer drug, ditercalinium.

Since ethidium bromide was not effective in mouse cell lines for isolating mitochondrial DNA (mtDNA)-less cells (rho zero cells), we examined whether an anticancer drug, ditercalinium (DC), which has been shown to exclude mtDNA from mouse cell lines, could be effective in various mouse and human cell lines. We found that after DC treatment rho zero cells could be isolated from all cell lines of mouse or human origin tested. Moreover, these rho zero cells maintained ability to receive exogenously imported mtDNA and allow its replication and gene expression. These observations suggest that DC eliminates mtDNA from mouse and human cells without affecting the property to receive exogenous mtDNA. Therefore, DC could be applicable to cell lines expressing various differentiated phenotypes for studying whether mtDNA plays a significant role in expression of phenotypes by manipulating mtDNA elimination and reintroduction.

3T3 Cells↗
PubMed1997

Isolation of mitochondrial DNA-less mouse cell lines and their application for trapping mouse synaptosomal mitochondrial DNA with deletion mutations.

For isolation of mouse mtDNA-less (rho0) cell lines, we searched for various antimitochondrial drugs that were expected to decrease the mtDNA content and found that treatment with ditercalinium, an antitumor bis-intercalating agent, was extremely effective for completely excluding mtDNA in all the mouse cell lines we tested. The resulting rho0 mouse cells were successfully used for trapping the mtDNA of living nerve cells into dividing cultured cells by fusion of the rho0 cells with mouse brain synaptosomes, which represent synaptic endings isolated from nerve cells. With neuronal mtDNA obtained, all of the cybrid clones restored mitochondrial translation activity similarly regardless of whether the mtDNA was derived from young or aged mice, thus at least suggesting that defects in mitochondrial genomes are not involved in the age-associated mitochondrial dysfunction observed in the brain of aged mice. Furthermore, we could trap a very small amount of a common 5823-base pair deletion mutant mtDNA (DeltamtDNA5823) that was detectable by polymerase chain reaction in the cybrid clones. As the amount of mutant mtDNA with large scale deletions was expected to increase during prolonged cultivation of the cybrids, these cells should be available for establishment of mice containing the deletion mutant mtDNA.

3T3 Cells↗
PubMed1988

Chromomycin A3 binds to left-handed poly(dG-m5dC).

The interaction of chromomycin A3 (an antitumor antibiotic) with right-handed and left-handed polynucleotides has been studied by absorbance, fluorescence, circular dichroism, 31P-NMR and 1H-NMR techniques. Binding to either the B form of poly(dG-dC) or the Z form of poly(dG-m5dC) shifts the absorbance maximum to higher wavelength and enhances the fluorescence of the drug. Circular dichroic spectra of solutions containing various concentrations of chromomycin A3 and fixed concentrations of either B or Z polynucleotides show well defined isoelliptic points at similar wavelengths. At the isoelliptic point, the drug complex with B DNA exhibits positive ellipticity while with Z DNA it exhibits negative ellipticity. 31P-NMR spectra of the chromomycin A3 complex with the Z form of poly(dG-m5dC) demonstrate that the Z conformation is retained in the drug complex up to one molecule drug/four base pairs. At Mg2+ concentrations lower than that necessary to stabilize the left-handed conformation of poly(dG-m5dC) alone, 31P analysis shows that chromomycin A3 can bind simultaneously to both the B and Z conformations of poly(dG-m5dC), with no effect on the B-Z equilibrium. These data demonstrate that chromomycin A3 binds to left-handed poly(dG-m5dC) with retention of the left-handed conformation up to saturating drug concentrations.

Binding Sites↗