Assignment of a Mus musculus gene for triosephosphate isomerase to chromosome 6 and for glyoxalase-I to chromosome 17 using somatic cell hybrids

Tpi-1 and Gapd are linked very closely on mouse chromosome 6

Mutations in the structural genes for triosephosphate isomerase and glyceraldehyde-3-phosphate dehydrogenase activity in the mouse, selected after mutagen treatment, were used to estimate the map distance between the two loci. It is shown that Tpi-1 and Gapd are closely linked on chromosome 6, with a recombination frequency of 0.1 +/- 0.1%.

Gene mapping of mouse laminin A and B2 subunits using mouse-Chinese hamster somatic cell hybrids

Laminin is a multichain extracellular matrix glycoprotein found primarily in basement membranes. The molecule is made up of three subunits, designated as A, B1, and B2. Using an 850-base cDNA probe for the mouse laminin A-chain and a 1000-base cDNA probe for the mouse laminin B2 chain, we have screened mouse-Chinese hamster somatic cell hybrids in order to assign the genes for each of these polypeptides to their respective mouse chromosome. We have determined that the mouse laminin B2-chain gene is located on chromosome 1 (confirming this assignment) and the laminin A-chain gene is located on chromosome 17.

An allele at the triose phosphate isomerase, Tpi-1 locus on chromosome 6 recovered from feral mice

An animal with low erythrocyte triose phosphate isomerase (TPI) activity was found amongst mice trapped on a farm in Leicestershire. The low TPI activity was caused by the segregation of a single co-dominant gene which also affected theKmfor glyceraldehyde-3-phosphate and heat stability of the enzyme. We designate the geneTpi-1, the structural locus for TPI, with theaallele in the common inbred strains and theballele derived from the wild-caught mouse.Tpi-1was known to be on chromosome 6 by somatic cell techniques and, as shown in a preliminary report (Peters & Bulfield, 1984), we have confirmed and extended this finding using three chromosome-6 marker genes giving the order:Sig-28-Lc-11-Miwh-16-Tpi-1.

Assignment of the mouse alpha A-crystallin structural gene to chromosome 17

alpha A2-crystallin is one of the major water-soluble proteins of the mammalian lens. Using a cloned cDNA probe coding for mouse alpha A2-crystallin and Southern blot hybridization, DNA isolated from a panel of somatic cell hybrids prepared from mouse fibroblasts or mouse spleen cells fused with Chinese hamster fibroblasts was probed to determine the chromosomal localization of the alpha A2-crystallin structural gene. We have located this gene on mouse chromosome 17.

Linkage of lactate dehydrogenase-2, Ldh-2, in the mouse

An electrophoretically detectable variant of lactate dehydrogenase-2 in Mus musculus has been found and used to locate the structural gene, Ldh-2, on chromosome 6. Gene order and recombination frequencies are estimated as Sig--36.0 +/- 4.8--Lc 21.0 +/- 4.1--Miwh--20.0 +/- 4.0--Ldh-2.

Polymorphism of lactate dehydrogenase B subunit in rat erythrocytes

Lactate dehydrogenase regulator geneLdr-1controls the amount of the lactate dehydrogenase A subunit in rat serum and the amount of lactate dehydrogenase B subunit in rat erythrocytes because no recombinant rats were found among 295 pups produced in the BDIV × (ACI × BDIV)F1 and (ACI × DI) Fl × DI backcrosses. Two alleles regulate the high (Ldr-1a) and low (Ldr-1b) activity enzyme. TheLdr-1is not linked to hooded coat pattern or glyoxalase-1. Sex andLdr-1assorted independently; hence the gene is autosomal.

Mouse immune interferon (IFN-gamma) gene is on chromosome 10

A cDNA clone for mouse immune interferon has been used to map the mouse interferon gamma gene (Ifg) to a specific chromosome. This clone, which contains a 638-bp insert detects an 18-kb HindIII fragment of mouse DNA. The presence of the mouse Ifg gene in cel hybrids and its chromosomal location were determined by assaying cell hybrid DNA for the presence of the 18-kb HindIII fragment by Southern filter hybridization. Under the hybridization conditions used, Chinese hamster DNA did not hybridize to the cDNA probe. The segregation of mouse chromosomes in cell hybrids indicated that Ifg is located on chromosome 10. Previously, we have mapped immune interferon to the p12.05----qter region of chromosome 12 in humans (1). This region of chromosome 12 also contains the genes for peptidase B and citrate synthase. The homologous genes in mouse are also located on chromosome 10, suggesting that these genes comprise a conserved linkage group.

Linkage and polymorphism of a gene controlling lactate dehydrogenase in the rat

The amount of lactate dehydrogenase subunit A in rat serum is under the control of the lactate dehydrogenase regulatory gene Ldr-1, and it is determined by two alleles, Ldr-1a (high) and Ldr-1b (low). Sex and LDH-A level segregate independently, so the Ldr-1 gene is autosomal. The genes for albino, red eye, hemoglobin, and Ldr-1 are linked (linkage group I), and their order is Ldr-1-Hbb-r-c. Our data put Ldr-1 45 cM from Hbb, and Hbb is 7 cM from c. Data in the literature separate r and c by 0.3 cM.

A new locus regulating the expression of the Ldh-2 gene in mouse liver

Patterns of lactate dehydrogenase (LDH) isozymes of tissues from various mouse strains were examined. An interstrain polymorphism for LDH isozymes of liver was established. One phenotype (CBA/Lac and AKR/J mice) yielded a five-banded LDH pattern, another phenotype (DBA/1J, DBA/2J, C57BL/6J and C3H/He) showed a three-banded one. Immunochemical evidence was obtained indicating that differences in the LDH pattern are mainly due to different contents of the B subunit of LDH. Linkage tests indicated that the locus Ldr-2 determining the amounts of the LDH B subunit in mouse liver tissue is located in chromosome 6, 19 + or - 4.1 cm away from the earlier described Ldr-1 locus. The effect of locus Ldr-2 is strictly tissue-specific; it is manifest only on days 6-8 after birth.

Patterns of chromosome segregation in Chinese hamster x mouse cell hybrids between permanent cell lines and thymus cells

Hybrids between a tumorigenic Chinese hamster cell line (DC3F-aza) and normal mouse thymus cells very rapidly lost most of their mouse chromosomes, whereas hybrids between tumorigenic mouse cell lines (either Cl.1D of L cell line origin, or PCC4-aza 1 teratocarcinoma cells) and normal Chinese hamster thymus cells lost most of their hamster chromosomes. From three such fusion experiments, 20 cell lines were developed which all followed the same evolution, namely, the elimination of the majority of the chromosomes contributed by the normal thymus cell. In some hybrids, the elimination process resulted in the total absence of intact chromosomes contributed by the thymus cell parent. Such hybrids were distinguished from revertant parental cells growing in the selective medium by the presence of at least one enzyme in their cell extracts which displayed the electrophoretic mobility of the enzyme of the thymus cell parent. These observations, together with data from other reports, suggest that, as a rule, interspecific cell hybrids which develop upon fusion between normal diploid cells and tumorigenic cell lines maintain the chromosomes of the latter and eliminate preferentially many or most of the chromosomes contributed by the normal cell parents, independent of the respective species of the parental cells.

Genes coding for sensitivity to interferon (IfRec) and soluble superoxide dismutase (SOD-1) are linked in mouse and man and map to mouse chromosome 16

By using 12 hamster-mouse hybrids segregating a mouse T(16;17)Bnr Robertsonian translocation chromosome in conjunction with 10 similar hybrids segregating normal mouse chromosomes, we have shown that the loci that control cellular sensitivity to interferon (IfRec) and code for the soluble enzyme superoxide dismutase (SOD-1) (superoxide:superoxide oxidoreductase; EC 1.15.1.1) are syntenic in the mouse and map to mouse chromosome 16. IfRec and SOD-1 are also syntenic in man. They have previously been assigned to the distal segment of the long arm of human chromosome 21, trisomy for which causes Down syndrome. Because both IfRec and SOD-1 map to mouse chromosome 16, it will now be possible to use mice trisomic for this chromosome to determine whether certain aspects of the Down syndrome phenotype in man are caused by an altered dosage of IfRec and SOD-1.