Remarkably little is known about mitochondrial transcription. The yeast enzyme is the only one with a defined structure. We have recently found that, like the bacterial sigma factors, the mitochondrial specificity factor is released from the transcription complex shortly after initiation. We have isolated a large collection of point mutations in the sigma-like specificity factor. We have used these to map the interface between the two subunits of the RNA polymerase and are currently using the mutations to understand how this simple enzyme recognizes the promoter and initiates transcription.
Mitochondrial transcription is subject to glucose repression.
We have concluded that regulation must involve factors in addition to the RNA polymerase regulated by nuclear genes. We are studying mutations that affect glucose repression to reveal the control mechanisms. Paf1p and Cdc73p are Found in a Novel RNA Polymerase II-Containing Complex Distinct from the Srbp Containing Holoenzyme. Nucleic Acids Res. DNA Dependent RNA Polymerases.