Mitochondrial intervention

Paul S. Brookes. brookes at uab.edu
Fri Feb 25 14:36:25 EST 2000


Magnus Lynch wrote:

 >It is proposed that certain of these mutations reduce the rate of free
 >radical production giving that mitochondrium a survival advantage
 >within the cell. Selection subsequently causes the mutant mitochondrial
 >genome to become the predominant species within that cell.

Has anyone ever shown "gain of function" in which a mtDNA mutation leads to 
less ROS production?  It was my understanding that just about all of them 
increased ROS production.   Of course by screening a library of yeast mtDNA 
mutants one might actually be able to find low ROS producers - has anyone 
tried this?

Quite why a low ROS producing mito' has a selective advantage over a 
medium-high ROS one is still puzzling to me.  Is there any evidence that if 
one artificially raises (antimycin A) or lowers (FCCP) mitochondrial ROS in 
a cell, that the mitochondrial turnover is changed, or the cell degrades / 
promotes replication of said mito's differently?

WRT to adding telemeres into mtDNA, I agree with Aubrey in that there are 
plenty of better ways to stop oxidative damage, such as common antioxidants 
(SOD, GPx, Lipids, GSH) and also physical barriers such as membranes, and 
stopping the ROS at its source.   Telomeres would seem to be a complicated 
way to go about things - and something that if it worked, you'd think 
nature would be doing it already.  Maybe there's a damn good reason not to 
have telomeres in mtDNA.

Paul


_________________________________________
Dr. Paul S. Brookes.            (brookes at uab.edu)
UAB Department of Pathology,   G004 Volker Hall
1670 University Blvd., Birmingham AL 35294 USA
Tel (001) 205 934 1915     Fax (001) 205 934 1775
http://peir.path.uab.edu/brookes

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