The human endonexin II (ENX2) gene is located at 4q28----q32

A relatively recently identified family of structurally similar Ca2(+)-dependent phospholipid binding proteins is called the annexin gene family. At least seven genes are known, although their exact functions are unclear. The endonexin II gene (ENX2), one member of the gene family, is assigned to 4q28----q32 using both Southern transfer analysis of human x rodent somatic cell hybrid DNAs and in situ chromosome hybridization. One of the lipocortin II genes, another annexin, had previously been assigned to the long arm of chromosome 4.     

The human mineralocorticoid receptor gene (MLR) is located on chromosome 4 at q31.2

The gene for the human mineralocorticoid receptor (MLR) was previously localized to chromosome 4. Here, we have localized this gene to 4q31.2 by in situ hybridization. This precise mapping of MLR will assist in the linkage analysis and genetic characterization of pseudohypoaldosteronism, an autosomal recessive disorder which likely results from a defect in the MLR gene.     

The gene for human carbonic anhydrase VI(CA6) is on the tip of the short arm of chromosome 1

The gene encoding the human secreted carbonic anhydrase isozyme CAVI(CA6) maps to chromosome 1 by Southern analysis of a somatic cell hybrid panel and to 1p36.22----p36.33 by in situ hybridization. CA6 is therefore not linked to the cytoplasmic carbonic anhydrase genes on chromosome 8 or to CA7 on chromosome 16.     

The gene cluster for human U2 RNA is located on chromosome 17q21

The gene cluster for human U2 RNA has been mapped to chromosome 17q21 by in situ hybridization and hybridization analysis of DNA from mouse/human somatic cell hybrids.     

Physical mapping of the human carbonic anhydrase gene cluster on chromosome 8

A cluster of genes encoding the three cytoplasmic carbonic anhydrase isozymes CAI, CAII, and CAIII lie on the long arm of chromosome 8 (8q22) in humans. These genes have been mapped using pulsed-field gel electrophoresis. The genes lie in the order CA2, CA3, CA1. CA2 and CA3 are separated by 20 kb and are transcribed in the same direction, away from CA1. CA1 is separated from CA3 by over 80 kb and is transcribed in the direction opposite to CA2 and CA3. The arrangement of the genes is consistent with proposals that the duplication event which gave rise to CA1 predated the duplication which gave rise to CA2 and CA3. The order of these three genes differs from that suggested for the mouse based on recombination frequency.     

The human dopamine D2 receptor gene is located on chromosome 11 at q22-q23 and identifies a TaqI RFLP.

Human dopaminergic neurons are involved in the control of hormone secretion, voluntary movement, and emotional behavior. Mediating these effects are the dopamine D1 and D2 receptors. These macromolecules belong to a large family of related sequences known as the G protein-coupled receptors. The D2 receptors have been of special interest because they bind, with high affinity and specificity, many of the commonly prescribed antipsychotic drugs. We previously isolated a full-length cDNA clone of the rat D2 receptor. When a chromosome mapping panel was probed with the rat D2 receptor cDNA a 15-kb EcoRI restriction fragment was identified and localized to human chromosome 11. The rat cDNA was also used to clone a human genomic fragment, lambda hD2G1, which contains the last coding exon of the D2 receptor gene (DRD2) and 16.5 kb of 3' flanking sequence. Hybridization of lambda hD2G1 to a chromosome 11 regional mapping panel localized DRD2 to 11q. In situ hybridization of lambda hD2G1 to metaphase chromosomes refined this assignment to the q22-q23 junction of chromosome 11. A search for RFLPs associated with D2DR identified a frequent two-allele TaqI RFLP.     

The human neurofilament gene (NEFL) is located on the short arm of chromosome 8

We have localized the gene coding for the human neurofilament light chain (NEFL) to chromosome band 8p2.1 by Southern blotting of DNA from hybrid cell panels and in situ hybridization to metaphase chromosomes.     

A high activity carbonic anhydrase isoenzyme (CA II) is present in mammalian spermatozoa

Summary Human and rat spermatozoa were stained for different carbonic anhydrase (CA) isoenzymes using specific antisera to human CA I, II and VI in conjunction with the immunofluorescence technique. The spermatozoa of both species were found to contain only CA II, which was located principally in the postacrosomal region of the human spermatozoa and in the acrosomal cap region of the rat spermatozoa. The presence of CA II could be confirmed by immunoblotting, which revealed a 29 K polypeptide in both the human and rat spermatozoa. No CA I or VI-specific fluorescence could be detected in the spermatozoa of either species. The immunoblottings were also negative. The results show mammalian spermatozoa to contain the high activity carbonic anhydrase isoenzyme II. Its presence is probably linked to hydration of CO₂ produced by active energy metabolism and thereby to the maintaining of an adequate intraspermatozoal bicarbonate concentration as required for the maintenance of sperm motility.     

A high activity carbonic anhydrase isoenzyme (CA II) is present in mammalian spermatozoa

Human and rat spermatozoa were stained for different carbonic anhydrase (CA) isoenzymes using specific antisera to human CA I, II and VI in conjunction with the immunofluorescence technique. The spermatozoa of both species were found to contain only CA II, which was located principally in the postacrosomal region of the human spermatozoa and in the acrosomal cap region of the rat spermatozoa. The presence of CA II could be confirmed by immunoblotting, which revealed a 29 K polypeptide in both the human and rat spermatozoa. No CA I or VI-specific fluorescence could be detected in the spermatozoa of either species. The immunoblottings were also negative. The results show mammalian spermatozoa to contain the high activity carbonic anhydrase isoenzyme II. Its presence is probably linked to hydration of CO2 produced by active energy metabolism and thereby to the maintaining of an adequate intraspermatozoal bicarbonate concentration as required for the maintenance of sperm motility.     

The human lactase-phlorizin hydrolase gene is located on chromosome 2

The lactase-phlorizin hydrolase gene was assigned to chromosome 2 by analysis of Southern blots of DNA from a panel of human-rodent cell hybrids containing characteristic sets of human chromosomes. The hybridization probe used was a recently isolated cDNA clone of the human lactase-phlorizin hydrolase gene.     

The structural gene for human coagulation factor X is located on chromosome 13q34

The gene coding for coagulation factor X was studied in a family segregating chromosomal abnormalities involving chromosomes 13 and 6. An individual monosomic for 13q34 was deficient in levels of clotting factors VII and X, while her brother, who is trisomic for 13q34, had elevated levels. DNA dosage studies with a cloned human factor X gene demonstrated that the low levels of factor X expression in the individual with the chromosome 13q34 deletion were due to the absence of one copy of the factor X structural gene. This confirms the assignment of the human gene coding for factor X to 13q34.     

The gene for human chromogranin A (CgA) is located on chromosome 14

Chromogranin A (CgA) is a protein that is present in most neuroendocrine tissues and is co-secreted with their resident hormones. We have assigned the CgA gene to human chromosome 14 by hybridization of a CgA cDNA probe cloned from a cDNA library of human medullary thyroid carcinoma cells to spots of individual human chromosomes flow-sorted onto nitrocellulose filters. Southern analysis of human genomic DNA with the same probe revealed only 1-3 restriction bands. These studies indicate that the CgA gene is probably single copy and not a member of a dispersed, multigene family. The CgA gene is not co-localized with the genes of any of the CgA-associated hormones.     

The primary erythermalgia-susceptibility gene is located on chromosome 2q31-32

Primary erythermalgia is a rare disorder characterized by recurrent attacks of red, warm, and painful hands and/or feet. The symptoms are generally refractory to treatment and persist throughout life. Five kindreds with multiple cases of primary erythermalgia were identified, and the largest was subjected to a genomewide search. We detected strong evidence for linkage of the primary erythermalgia locus to markers from chromosome 2q. The highest LOD score (Z) was obtained with D2S2330 (Z(max) = 6.51). Analysis of recombination events identified D2S2370 and D2S1776 as flanking markers, on chromosome 2q31-32. This defines a critical interval of 7.94 cM that harbors the primary erythermalgia gene. Affected members within the additional families also shared a common haplotype on chromosome 2q31-32, supporting our linkage results. Identification of the primary erythermalgia gene will allow a better clinical classification of this pleomorphic group of disorders.     

The angiotensinogen gene is located on mouse chromosome 8

We have recently identified a cis-acting genetic lesion affecting angiotensinogen gene expression in testis and salivary gland. Accordingly, the angiotensinogen gene was assigned to mouse chromosome 8 by screening a series of hybrid cell lines for retention of mouse angiotensinogen sequences by genomic Southern analysis. In AKXD recombinant inbred mice, the angiotensinogen gene is 2.4 +/- 1.8 centiMorgan from Rn7S-8,a 7S RNA gene located on chromosome 8 (Taylor, B.A., personal communication). However, the segregation of salivary and testicular angiotensinogen expression phenotypes into inbred mouse strains was not concordant with the known chromosome 8 proviruses Emv-2, Mtv-21, Xmv-12 or Xmv-26.     

The human calbindin D28k (CALB1) and calretinin (CALB2) genes are located at 8q21.3----q22.1 and 16q22----q23, respectively, suggesting a common duplication with the carbonic anhydrase isozyme loci

The genes encoding calbindin D28k (CALB1) and calretinin (CALB2), two closely related calcium-binding proteins, were mapped by in situ hybridization to the 8q21.3----q22.1 and 16q22----q23 regions of the human genome, respectively. These localizations match the chromosomal regions where the carbonic anhydrase isozyme gene cluster (CA1, CA2, CA3) and the related gene CA7 have been described, respectively. This suggests a common duplication o the calbindin/calretinin and the carbonic anhydrase ancestral genes.     

The terminal deoxynucleotidyltransferase gene is located on human chromosome 10 (10q23----q24) and on mouse chromosome 19

Terminal deoxynucleotidyltransferase (TdT) is a DNA polymerase expressed in immature lymphocytes of the thymus and bone marrow, as well as certain leukemic cells. Chromosomal assignment of the gene coding for human TdT was accomplished by in situ hybridization of a 3H-labeled cDNA probe to human chromosome preparations and by Southern blot analysis of somatic cell hybrid DNAs. The human TdT gene was mapped to the region q23----q24 of chromosome 10. Breaks at this site have been reported in different translocations in human leukemias. The mouse TdT gene was assigned to chromosome 19 by Southern blot analysis of mouse X Chinese hamster somatic cell hybrids. This result adds a fourth locus to the conserved syntenic group on mouse chromosome 19 and human chromosome 10.     

Localization of human c-mos to chromosome band 8q11 in leukemic cells with the t(8;21) (q22;q22)

Summary Chromosome in situ hybridization studies locate c-mos to chromosome band 8q11 in leukemic cells carrying the t(8;21) (q22;q22). This amends the previous assignment of c-mos to chromosome band 8q22 and conforms with its recent assignment to 8q11 in normal cells and in a cell line with a structurally abnormal chromosome 8. C-mos lies proximally to, and distant from, the breakpoint at 8q22 in the t(8;21) and is unlikely to have a role in the onset of acute myeloid leukemia characterized by this translocation.