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Localization of two genes encoding plasma membrane Ca2(+)-transporting ATPases to human chromosomes 1q25-32 and
S Olson1, M G Wang, E Carafoli
1Laboratory of Biochemistry, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892.
Abstract:
Human plasma membrane Ca2(+)-ATPase (PMCA) isoforms are encoded by at least four separate genes and the diversity of these enzymes is further increased by alternative splicing of transcripts. Cloned cDNAs for two of these isoforms have been used as probes to localize chromosomally the human PMCA1 (ATP2B1) gene to 12q21-q23 and PMCA4 (ATP2B2) to 1q25-q32. These results were obtained by three independent methods, including Southern analysis of human-rodent somatic cell hybrids, in situ hybridization of human metaphase spreads, and genetic linkage analysis in the CEPH pedigrees. High-frequency RFLPs detected at each locus were used in these linkage analyses. No evidence was obtained for multiple copies of the gene at either locus. A cross-hybridizing sequence was detected with PMCA4 probes on Xq13-qter at low stringency. Further studies are required to determine whether this X-chromosomal sequence represents a third member of the PMCA gene family.
Insights
Researchers mapped human plasma membrane Ca2(+)-ATPase (PMCA) genes. PMCA1 (ATP2B1) is on chromosome 12q21-q23 and PMCA4 (ATP2B2) is on 1q25-q32, aiding in understanding calcium transport diversity.
Area of Science:
- Genetics
- Molecular Biology
- Biochemistry
Background:
- Human plasma membrane Ca2(+)-ATPase (PMCA) isoforms are crucial for calcium homeostasis.
- Multiple genes and alternative splicing contribute to PMCA enzyme diversity.
Purpose of the Study:
- To chromosomally localize human PMCA1 (ATP2B1) and PMCA4 (ATP2B2) genes.
- To investigate potential additional PMCA gene family members.
Main Methods:
- Southern analysis of human-rodent somatic cell hybrids.
- In situ hybridization of human metaphase spreads.
- Genetic linkage analysis using CEPH pedigrees and RFLPs.
Main Results:
- Human PMCA1 (ATP2B1) gene localized to 12q21-q23.
- Human PMCA4 (ATP2B2) gene localized to 1q25-q32.
- A potential third PMCA gene sequence detected on the X chromosome.
Conclusions:
- Established chromosomal locations for PMCA1 and PMCA4 genes.
- Suggests the existence of additional PMCA gene family members requiring further investigation.