Lack of mitochondrial trifunctional protein in mice causes neonatal hypoglycemia and sudden death

Mitochondrial trifunctional protein (MTP) is a hetero-octamer of four alpha and four beta subunits that catalyzes the final three steps of mitochondrial long chain fatty acid beta-oxidation. Human MTP deficiency causes Reye-like syndrome, cardiomyopathy, or sudden unexpected death. We used gene targeting to generate an MTP alpha subunit null allele and to produce mice that lack MTP alpha and beta subunits. The Mtpa(-/-) fetuses accumulate long chain fatty acid metabolites and have low birth weight compared with the Mtpa(+/-) and Mtpa(+/+) littermates. Mtpa(-/-) mice suffer neonatal hypoglycemia and sudden death 6-36 hours after birth. Analysis of the histopathological changes in the Mtpa(-/-) pups revealed rapid development of hepatic steatosis after birth and, later, significant necrosis and acute degeneration of the cardiac and diaphragmatic myocytes. This mouse model documents that intact mitochondrial long chain fatty acid oxidation is essential for fetal development and for survival after birth. Deficiency of MTP causes fetal growth retardation, neonatal hypoglycemia, and sudden death.

Comparison of human cytomegalovirus (HCMV) protease sequences among laboratory strains and seven clinical isolates

The nucleotide sequence of the human cytomegalovirus (HCMV) protease gene from two laboratory strains and seven clinical isolates, both ganciclovir-sensitive and -resistant, was examined to determine the genetic variability of the HCMV protease catalytic domain and to identify changes that may alter the efficacy of designed protease inhibitors. The Towne strain varied from AD169 at 12 nucleotides and led to one amino acid change at position 12 (Ala to Thr). The clinical isolates had amino acid substitutions relative to the laboratory strains, with a Ser to Pro change at position 8, a His to Tyr change at position 44 and s Gly to Ser change at position 47. None of these changes occurred in any of the conserved domains of the protease, nor do they appear necessary to confer ganciclovir resistance in the isolates. These findings suggest that no changes exist in the protease of the clinical isolates examined that may diminish the effectiveness of a drug targeting the HCMV protease. 1977 Elsevier Science B.V. All rights reserved.