Kyoji Kondo

Frequency distribution of histocompatibility-2 antigenic specificities in the Japanese wild mouse genetically remote from the European subspecies.

Fifty‐eight Japanese wild mice, Mus musculus molossinus, collected from twenty‐eight localities were surveyed for twelve H‐2 antigens using the haemagglutination method. Significantly higher frequencies of H‐2.3 and H‐2.5 specifities and relatively lower frequencies of the other public specificities were observed. This was confirmed by examining four specificities, H‐2.3, 5, 13 and 23, in 370 mice. Quantitative absorption of the alloantisera by erythrocytes and spleen lymphocytes of molossinu mouse revealed definite absorption of H‐2.3, 5 and 8 antigens, though their antigenic strength was apparently weaker than the controls, B10 congenic mice. Comparative assay of the strength of H‐2.5 antigen in either homozygous and heterzygous conditions distinctly eliminated the possibility of gene‐dose effect for the reduced strength of the public antigens in molossinus mouse. To explain this, divergence time between molossinus and domesticus was computed based on the allelic frequency data already reported on ten loci in both subspecies. It is roughly 1.5 × 106 years, which could allow for the occurrence of considerable genetic changes in many public antigens, except those conserved through selection.

Restriction fragment length variations and chromosome mapping of two mouse metallothionein genes,Mt-1 andMt-2

Restriction endonuclease fragment length variations (RFLVs) were found through the use of cDNA probes for metallothionein genes 1 (Mt-1) and 2 (Mt-2) in the mouse. RFLVs were detected in restriction patterns generated byBglII andXbaI in theMt-1 gene and byPvuII in theMt-2 gene. All laboratory strains carry theMt-1a andMt-2a alleles. Among strains of wild origin, some Western European subspecies (Mus mus domesticus andM. m. brevirostris) also carry theMt-1a andMt-2a alleles. In contrast, a European subspecies (M. m. musculus) and the great majority of subspecies from East Asian countries (M. m. molossinus, Chinese mice of wild origin, andM. m. yamashinai) carry theMt-1b andMt-2b alleles. Adomesticus strain from Bulgaria and twocastaneus strains from Thailand and Philippines carry the intermediate combination ofMt-1b andMt-2a alleles. Using the RFLVs, we mapped theMt-1 andMt-2 genes on chromosome 8, and they appear to be very closely linked since no recombination was observed between them in any of the mice examined. Data from three-point cross tests showed that the recombination frequencies are 4.31% betweenOs andMt, 15.52% betweenMt andPrt-2, and 19.83% betweenOs andPrt-2. The gene order ofOs-Mt-1,Mt-2-Prt-2 has been confirmed.

Autosomal Recessive Polycystic Kidney in Rats

We evaluated the characteristics of renal lesions in rat autosomal recessive polycystic kidney (ARPK). In rat ARPK, small cysts appeared primarily in the medulla 2 months after birth and gradually extended to the cortex, forming large cysts involving the entire layer after 8 months. By immunofluorescence microscopy, type IV collagen was more strongly stained in the epithelial basement membrane of the rat ARPK than in the normal rat tubular basement membrane (TBM). Electron microscopy demonstrated a marked thickening, slight splitting and lamination of the TBM in the ARPK. As peroxidase-labeled lectins, dolichos biflorus very strongly stained the cyst epithelium whereas lens culinaris did not. These findings indicate that cysts in rat ARPK originate in the collecting duct.

Cystic Basement Membrane with Increased Negative Charge in Rat Autosomal Recessive Polycystic Kidney

Cystic Basement Membrane with Increased Negative Charge in Rat Autosomal Recessive Polycystic Kidney Z. Zenshiro Inage Y. Yumio Kikkawa M. Motoyuki Minato M. Misao Owada T. Teruo Kitagawa K. Kyoko Ohno K. Kyoji Kondo Y. Yoshihiko Ueda K. Kazunari Iidaka Department of Pediatrics, Nihon University, School of Medicine, Tokyo; Laboratory of Experimental Animals, Yagi Memorial Park, Gifu; Second Department of Pathology, Dokkyo University, School of Medicine Tochigi, Japan

Importance of Biochemical Marker Genes in Inbred Strains of Mice: Some Problems on Checking Genetic Purity of Inbred Strains@@@―系統の遺伝的チェックの際生じた問題点

In order to check genetic purity of inbred strains of mice, we surveyed five biochemical variants in certain 69 strains, some of which had established from Japanese fancy mice. The loci examined were Hemoglobin beta-chain, Malic enzyme (supernatant form), Isocitrate dehydrogenase (supernatant form), Serum esterase-1, and Serum esterase-2. These loci were all in homozygous states as far as examined, however some subline divergences were found in a few strains, that is to say, sublines were found to be fixed with different alleles as some loci, Important of biochemical marker genes to check genetic purity of strains and several derived problems are mentioned.