Mutation of the GM2 activator protein in a feline model of GM2 gangliosidosis.
The G(M2) activator protein is required for successful degradation of G(M2) ganglioside by the A isozyme of lysosomal beta-N-acetylhexosaminidase (EC 3.2.1.52). Deficiency of the G(M2) activator protein leads to a relentlessly progressive accumulation of G(M2) ganglioside in neuronal lysosomes and subsequent fatal deterioration of central nervous system function. G(M2) activator deficiency has been described in humans, dogs and mice. This manuscript reports the discovery and characterization of a feline model of G(M2) activator deficiency that exhibits many disease traits typical of the disorder in other species. Cats deficient in the G(M2) activator protein develop clinical signs at approximately 14 months of age, including motor incoordination and exaggerated startle response to sharp sounds. Affected cats exhibit central nervous system abnormalities such as swollen neurons, membranous cytoplasmic bodies, increased sialic acid content and elevated levels of G(M2) ganglioside. As is typical of G(M2) activator deficiency, hexosaminidase A activity in tissue homogenates appears normal when assayed with a commonly used synthetic substrate. When the G(M2) activator cDNA was sequenced from normal and affected cats, a deletion of 4 base pairs was identified as the causative mutation, resulting in alteration of 21 amino acids at the C terminus of the G(M2) activator protein.
Martin
Douglas R
DR
Scott-Ritchey Research Center, College of Veterinary Medicine, Auburn University, Auburn, AL 36849-5525, USA. martidr@auburn.edu
Cox
Nancy R
NR
Morrison
Nancy E
NE
Kennamer
David M
DM
Peck
Stephanie L
SL
Dodson
Arlene N
AN
Gentry
Atoska S
AS
Griffin
Brenda
B
Rolsma
Mark D
MD
Baker
Henry J
HJ
D000375:Aging; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001923:Brain Chemistry; D002415:Cats; D002490:Central Nervous System / Q000473:pathology / Q000503:physiopathology; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D004195:Disease Models, Animal; D005260:Female; D049289:G(M2) Activator Protein / Q000737:chemistry / Q000172:deficiency / Q000235:genetics* / Q000502:physiology; D005678:G(M2) Ganglioside / Q000032:analysis / Q000378:metabolism; D020143:Gangliosidoses, GM2 / Q000235:genetics* / Q000378:metabolism; D017353:Gene Deletion; D006596:Hexosaminidases / Q000032:analysis; D008099:Liver / Q000201:enzymology; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D019158:N-Acetylneuraminic Acid / Q000032:analysis; D009474:Neurons / Q000737:chemistry / Q000473:pathology; D010375:Pedigree; D013950:Thymus Gland / Q000201:enzymology
D018076:DNA, Complementary; D049289:G(M2) Activator Protein; D005678:G(M2) Ganglioside; D006596:Hexosaminidases; D019158:N-Acetylneuraminic Acid