Assignment of the CD45-AP Gene to the Centromeric End of Mouse Chromosome 19 and Human Chromosome 11q13.1–q13.3

CD45-AP is a recently identified phosphorylated protein that specifically associates with the leukocyte-specific transmembrane glycoprotein CD45. The gene for CD45-AP,Ptprcap(protein tyrosine phosphatase, receptor type c polypeptide associated protein), was mapped in mouse by typing the progeny of two multilocus crosses using the mouse CD45-AP cDNA as a Southern hybridization probe. The CD45-AP gene mapped to the centromeric region of Chr 19 proximal to the genesFth, Cd5,andPcna-rs.The gene for the human CD45-AP homologue,PTPRCAP,was localized to chromosome band 11q13.1–q13.3 by fluorescencein situhybridization using human genomic CD45-AP DNA as a hybridization probe. The genetic mapping of thePtprcap/PTPRCAPgenes extends the previously defined synteny conservation of various genes that have been assigned to these regions of the mouse and the human chromosomes.     

The Gene Encoding the Catalytic Subunit Cα of cAMP-Dependent Protein Kinase (Locus PRKACA) Localizes to Human Chromosome Region 19p13.1

We have determined the chromosomal localization of the gene for the catalytic subunit Cα of cAMP-dependent protein kinase (locus PRKACA) to human chromosome 19 using polymerase chain reaction (PCR) and Southern blot analysis of two different somatic cell hybrid mapping panels. In addition, PCR analysis of a chromosome 19 mapping panel revealed the presence of a human Cα-specific amplification product only in cell lines containing the region 19p13.1 to 19q12. Finally, two-color fluorescencein situhybridization to metaphase chromosomes using the human Cα cDNA and human chromosome 19 inter-Alu-PCR product as probes localized the human Cα gene to chromosome region 19p13.1.     

Molecular Characterisation of the 76 kDa Iron-Sulphur Protein Subunit of Potato Mitochondrial Complex I

Genes encoding subunits of complex I (EC 1.6.5.3 [EC] ) of the mitochondrialrespiratory chain vary in their locations between the mitochondrialand nuclear genomes in different organisms, whereas genes fora homologous multisub-unit complex in chloroplasts have to dateonly been found on the plastid genome. In potato (Solatium tuberosumL.), the gene coding for the mitochondrial 76 kDa iron-sulphurprotein is identified in the nuclear genome. The gene is transcribedinto polyadenylated mRNA which is most abundant in flowers,and more frequent in tubers than in leaves. The amino acid sequenceis well conserved relative to the nuclear-encoded 75 kDa and78 kDa subunits of Bos taurus and Neurospora crassa, respectively,and to the Paracoccus denitrificans homologue, most prominentlyin the region presumed to carry the iron-sulphur clusters. Polyclonalantibodies directed against the 78 kDa complex I subunit ofN. crassa recognise the 76 kDa polypeptide in potato mitochondrialcomplex I, and additionally a polypeptide of 75 kDa in solubilisedstroma thylakoids from spinach chloroplasts. The 32 amino acidresidues long presequence of the potato mitochondrial 76 kDacomplex I subunit targets the precursor polypeptide into isolatedpotato mitochondria but not into isolated chloroplasts. Theseresults suggest that chloroplast stroma thylakoids contain aprotein similar in size and antigenicity to, but geneticallydistinct from, the mitochondrial subunit. ¹ To whom correspondence should be addressed. ⁴ Present address: Max-Planck-Institut für Molekulare Genetik,Ihnestrasse 73, D-14195, Berlin, Germany. ⁵ Present address: Bioinside GmbH, Potsdamer Strasse 18A, D-14513Teltow, Germany.     

Mapping of theARIXHomeodomain Gene to Mouse Chromosome 7 and Human Chromosome 11q13

The recently described homeodomain protein ARIX is expressed specifically in noradrenergic cell types of the sympathetic nervous system, brain, and adrenal medulla. ARIX interacts with regulatory elements of the genes encoding the noradrenergic biosynthetic enzymes tyrosine hydroxylase and dopamine β-hydroxylase, suggesting a role for ARIX in expression of the noradrenergic phenotype. In the study described here, the mouse and human ARIX genes are mapped. Using segregation analysis of two panels of mouse backcross DNA, mouseArixwas positioned approximately 50 cM distal to the centromere of chromosome 7, nearHbb.HumanARIXwas positioned through analysis of somatic cell hybrids and fluorescencein situhybridization of human metaphase chromosomes to chromosome 11q13.3–q13.4. These map locations extend and further define regions of conserved synteny between mouse and human genomes and identify a new candidate gene for inherited developmental disorders linked to human 11q13.