Mouse chromosome 10

The L-isoaspartyl/D-aspartyl protein methyltransferase gene (PCMT1) maps to human chromosome 6q22.3-6q24 and the syntenic region of mouse chromosome 10

We have mapped the genes for the human and mouse L-isoaspartyl/D-aspartyl protein carboxyl methyltransferase (EC 2.1.1.77) using cDNA probes. We determined that the human gene is present in chromosome 6 by Southern blot analysis of DNA from a panel of mouse-human somatic cell hybrids. In situ hybridization studies allowed us to confirm this identification and further localize the human gene (PCMT1) to the 6q22.3-6q24 region. By analyzing the presence of an EcoRI polymorphism in DNA from backcrosses of C57BL/6J and Mus spretus strains of mice, we localized the mouse gene (Pcmt-1) to chromosome 10, at a position 8.2 +/- 3.5 cM proximal to the Myb locus. This region of the mouse chromosome is homologous to the human 6q24 region.

A molecular genetic linkage map of mouse chromosome 10, including the Myb, S100b, Pah, Sl, and Ifg genes

Restriction endonuclease fragment length variations (RFLV) on mouse chromosome 10 were detected in four genes, namely, the Myb protooncogene (Myb) and the genes for S100 beta protein (S100b), phenylalanine hydroxylase (Pah), and interferon-gamma (Ifg). RFLV were found in restriction patterns generated with BamHI for Myb, in those generated with BglII for S100b, in those generated with EcoRV for Pah, and in those generated with TaqI for Ifg. A multipoint backcross was carried out by the mating (129/Sv-Sl/+ x MOL-MIT)F1 x 129/SvJ(-)+/+. The Sl mutation has phenotypic effects which include deficiencies in pigment cells, germ cells, and blood cells. The following order of genes was derived from the results of the multipoint backcross, with distances between genes in parentheses: centromere--Myb--(34.9 cM)--S100b--(8.5 cM)--Pah--(8.5 cM)--Sl--(12.3 cM)--Ifg--telomere. Most laboratory strains and two strains of Mus musculus domesticus of wild origin carry the Myba, S100a, Paha, and Ifga alleles. In contrast, a strain of M. m. musculus, two strains of M. m. yamashinai, and two strains of M. m. molossinus carry the Mybb, S100b, Pahb, and Ifgb alleles. Other strains of wild origin carry various combinations of these alleles.

Chromosomal mapping of the human (MACS) and mouse (Macs) genes encoding the MARCKS protein

The myristoylated, alanine-rich C-kinase substrate, or MARCKS protein, is a major cellular substrate for protein kinase C that is also a high-affinity calmodulin-binding protein. In addition, it is the prototype of a small family of myristoylated, calmodulin-binding protein kinase C substrate proteins. We isolated a phage clone from a mouse genomic library that spanned the entire coding sequence of the mouse MARCKS protein. The first 612 bp of the putative promoter was 89% identical to a corresponding region of the human promoter, and contained at least 59 potential transcription factor binding sites in analogous locations; both human and mouse promoters lacked TATA boxes. The mouse genomic probe was used to localize the mouse gene to chromosome 10, in the middle of a linkage group that corresponds to a region on human chromosome 6q. These data strongly suggested that the human gene would localize to 6q21. This was confirmed by studies of DNA from a patient with del(6)(q21), in which expression of the human gene encoding MARCKS, MACS, was only about 50% of normal; MARCKS mRNA expression in lymphoblast RNA from this patient was only 22% of normal. These studies confirm that the mouse and human MARCKS proteins are products of the same genes in their respective species; differences in their primary sequence can therefore be attributed to species variation rather than to the existence of related genes.