Mutations in a plasma membrane Ca2+-ATPase gene cause deafness in deafwaddler mice.
Hearing loss is the most common sensory deficit in humans. Because the auditory systems of mice and humans are conserved, studies on mouse models have predicted several human deafness genes and identified new genes involved in hearing. The deafwaddler (dfw) mouse mutant is deaf and displays vestibular/motor imbalance. Here we report that the gene encoding a plasma membrane Ca2+-ATPase type 2 pump (Atp2b2, also known as Pmca2) is mutated in dfw. An A-->G nucleotide transition in dfw DNA causes a glycine-to-serine substitution at a highly conserved amino-acid position, whereas in a second allele, dfw2J, a 2-base-pair deletion causes a frameshift that predicts a truncated protein. In the cochlea, the protein Atp2b2 is localized to stereocilia and the basolateral wall of hair cells in wild-type mice, but is not detected in dfw2J mice. This indicates that mutation of Atp2b2 may cause deafness and imbalance by affecting sensory transduction in stereocilia as well as neurotransmitter release from the basolateral membrane. These mutations affecting Atp2b2 in dfw and dfw2J are the first to be found in a mammalian plasma membrane calcium pump and define a new class of deafness genes that directly affect hair-cell physiology.
The Virginia Merrill Bloedel Hearing Research Center and Department of Otolaryngology-Head and Neck Surgery, University of Washington School of Medicine, Seattle 98195-7923, USA.
V A
VA
Street
J W
JW
McKee-Johnson
R C
RC
Fonseca
B L
BL
Tempel
K
K
Noben-Trauth
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000201:enzymology; D000252:Calcium-Transporting ATPases / Q000032:analysis / Q000235:genetics*; D002462:Cell Membrane / Q000201:enzymology; D002874:Chromosome Mapping; D004252:DNA Mutational Analysis; D003638:Deafness / Q000235:genetics*; D004195:Disease Models, Animal; D016368:Frameshift Mutation / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic; D005796:Genes / Q000235:genetics; D051379:Mice; D008818:Mice, Neurologic Mutants; D008969:Molecular Sequence Data; D009925:Organ of Corti / Q000201:enzymology; D017354:Point Mutation / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D014722:Vestibule, Labyrinth / Q000201:enzymology
D012333:RNA, Messenger; D000252:Calcium-Transporting ATPases