LOCALIZATION OF 2 GENES ENCODING PLASMA-MEMBRANE CA2-2 (ATP2B2) AND ISOFORM-3 (ATP2B3) TO HUMAN-CHROMOSOME-3P26-]P25 AND HUMAN-CHROMOSOME-XQ28, RESPECTIVELY( ATPASES ISOFORM)

The plasma membrane Ca2+ ATPases (PMCA) represent a highly conserved, widely dispersed, multigene family in eukaryotes consisting of at leas t four functional genes. The genes for PMCA isoforms 1 and 4 (ATP2B1 a nd ATP2B4) have been previously localized to human chromosomes 12q21 - -> q23 and 1q25 --> q32, respectively. Based upon results of fluoresce nce in situ hybridization (FISH), analysis of somatic cell hybrids, an d genetic linkage analyses, we now report localization of ATP2B3 (PMCA isoform 3) to human chromosome Xq28, and confirm the recent localizat ion of ATP2B2 (PMCA isoform 2) to chromosome 3p26 --> p25. In contrast to ATP2B1 and ATP2B4, recent studies have suggested tissue specific r egulation of expression of both ATP2B2 and ATP2B3 particularly in the nervous system. The genes for several neurological and neuromuscular d iseases have been assigned to the distal portion of Xq, and ATP2B3 is a candidate gene for these diseases.