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Mol Cell Biol

Title:		Mitochondrial DNA instability and peri-implantation lethality associated with targeted disruption of nuclear respiratory factor 1 in mice
Author(s):		Huo L; Scarpulla RC;
Address:		"Department of Cell and Molecular Biology, Northwestern Medical School, Chicago, Illinois 60611, USA"
Journal Title:		Mol Cell Biol
Year:		2001
Volume:		21
Issue:		2
Page Number:		644 - 654
DOI:		10.1128/MCB.21.2.644-654.2001
ISSN/ISBN:		0270-7306 (Print) 1098-5549 (Electronic) 0270-7306 (Linking)
Abstract:		"In vitro studies have implicated nuclear respiratory factor 1 (NRF-1) in the transcriptional expression of nuclear genes required for mitochondrial respiratory function, as well as for other fundamental cellular activities. We investigated here the in vivo function of NRF-1 in mammals by disrupting the gene in mice. A portion of the NRF-1 gene that encodes the nuclear localization signal and the DNA-binding and dimerization domains was replaced through homologous recombination by a beta-galactosidase-neomycin cassette. In the mutant allele, beta-galactosidase expression is under the control of the NRF-1 promoter. Embryos homozygous for NRF-1 disruption die between embryonic days 3.5 and 6.5. beta-Galactosidase staining was observed in growing oocytes and in 2. 5- and 3.5-day-old embryos, demonstrating that the NRF-1 gene is expressed during oogenesis and during early stages of embryogenesis. Moreover, the embryonic expression of NRF-1 did not result from maternal carryover. While most isolated wild-type and NRF-1(+/-) blastocysts can develop further in vitro, the NRF-1(-/-) blastocysts lack this ability despite their normal morphology. Interestingly, a fraction of the blastocysts from heterozygous matings had reduced staining intensity with rhodamine 123 and NRF-1(-/-) blastocysts had markedly reduced levels of mitochondrial DNA (mtDNA). The depletion of mtDNA did not coincide with nuclear DNA fragmentation, indicating that mtDNA loss was not associated with increased apoptosis. These results are consistent with a specific requirement for NRF-1 in the maintenance of mtDNA and respiratory chain function during early embryogenesis"
Keywords:		"Animals Blastocyst/*cytology/*metabolism Cell Division DNA Fragmentation DNA, Mitochondrial/analysis/*genetics DNA-Binding Proteins/*genetics/metabolism Embryonic and Fetal Development Female *Fetal Death Gene Deletion Gene Dosage Gene Targeting Genotype;"
Notes:		"MedlineHuo, L Scarpulla, R C eng R01 GM032525/GM/NIGMS NIH HHS/ R56 GM032525/GM/NIGMS NIH HHS/ GM32525-18/GM/NIGMS NIH HHS/ Research Support, U.S. Gov't, P.H.S. 2001/01/03 Mol Cell Biol. 2001 Jan; 21(2):644-54. doi: 10.1128/MCB.21.2.644-654.2001"