| The mitochondria of Neurospora crassa contain two respiratory pathways, the normal electron-transport chain and an inducible cyanide-resistant alternative oxidase pathway. In Neurospora, the assembly of the alternative oxidase pathway requires the expression of two genes, aod-1, which encodes the alternative oxidase, and aod-2, which is involved in the transcriptional regulation of aod-1. The objective of this work was the cloning and characterization of the aod-2 gene. An attempt was made to isolate the aod-2 + DNA in two different ways: chromosome walking, and by complementation of an aod-2 mutant using aod-1 promoter-driven expression of the bacterial hygromycin resistance gene as a method for selecting transformants;Most of the proteins involved in mitochondrial gene replication and expression are encoded by nuclear genes. I have cloned, sequenced and partially characterized the DNA polymerase-gamma gene (mip-1) that codes for the presumptive mitochondrial DNA polymerase of Neurospora crassa. Sequence analysis showed that mip-1 includes a 3918-nucleotide open reading frame encoding a 1305 amino-acid, 146 kDa protein that has a mitochondrial targeting element at the amino terminus. |
