Effect of genetic background on phenotype variability in transgenic mouse models of amyotrophic lateral sclerosis: a window of opportunity in the search for genetic modifiers.
Transgenic (Tg) mouse models of FALS containing mutant human SOD1 genes (G37R, G85R, D90A, or G93A missense mutations or truncated SOD1) exhibit progressive neurodegeneration of the motor system that bears a striking resemblance to ALS, both clinically and pathologically. The most utilized and best characterized Tg mice are the G93A mutant hSOD1 (Tg(hSOD1-G93A)1GUR mice), abbreviated G93A. In this review we highlight what is known about background-dependent differences in disease phenotype in transgenic mice that carry mutated human or mouse SOD1. Expression of G93A-hSOD1Tg in congenic lines with ALR, NOD.Rag1KO, SJL or C3H backgrounds show a more severe phenotype than in the mixed (B6xSJL) hSOD1Tg mice, whereas a milder phenotype is observed in B6, B10, BALB/c and DBA inbred lines. We hypothesize that the background differences are due to disease-modifying genes. Identification of modifier genes can highlight intracellular pathways already suspected to be involved in motor neuron degeneration; it may also point to new pathways and processes that have not yet been considered. Most importantly, identified modifier genes provide new targets for the development of therapies.
Drexel University College of Medicine, Philadelphia, Pennsylvania, USA. theiman@drexelmed.edu
Terry D
TD
Heiman-Patterson
Roger B
RB
Sher
Elizabeth A
EA
Blankenhorn
Guillermo
G
Alexander
Jeffrey S
JS
Deitch
Catherine B
CB
Kunst
Nicholas
N
Maragakis
Gregory
G
Cox
D000690:Amyotrophic Lateral Sclerosis / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D000818:Animals; D004195:Disease Models, Animal; D015195:Drug Design; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009410:Nerve Degeneration / Q000235:genetics / Q000473:pathology; D010641:Phenotype; D020033:Protein Isoforms / Q000235:genetics; D013482:Superoxide Dismutase / Q000235:genetics*; D000072105:Superoxide Dismutase-1; D015996:Survival Rate
D020033:Protein Isoforms; C000606290:SOD1 protein, human; C000606291:Sod1 protein, mouse; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1