mt-mRNA stability regulates the expression of the mitochondrial genome during liver development.

We have recently reported that regulation of the expression of the nuclear-encoded beta-F1-ATPase gene during development of rat liver is exerted also by the control of beta-F1-ATPase mRNA decay (Izquierdo, J.M., Ricart, J., Ostronoff, L.K., Egea, G. and Cuezva, J.M. (1995) J. Biol. Chem. 270, 10342-10350). In this paper, we report that high steady-state levels of the mitochondrial encoded mRNAs for subunits of the ATP synthase (ATP 6-8) in developing liver result from profound changes in the stability of the mitochondrial transcripts. The results strongly suggest that developmental regulation of nuclear and mitochondrial genes during biogenesis of mammalian mitochondria is concertedly controlled by a posttranscriptional mechanism that involves the regulation of mRNA degradation of both genomes.