title: Quantitative trait loci analysis of heat stress resistance of spermatocytes in the MRL/MpJ mouse.
abstract: The MRL/MpJ mouse has previously been reported to possess an interesting phenotype in which spermatocytes are resistant to the abdominal temperature heat shock. In this study genetic analysis for it was performed. The phenotypes of F2 progenies produced by mating MRL/MpJ and control strain C57BL/6 mice were not segregated into two types as parental phenotypes, suggesting that the phenotype is controlled by multiple genetic loci. Thus, quantitative trait loci (QTL) analysis was performed using 98 microsatellite markers. The weight ratio of the cryptorchid testis to the intact testis (testis weight ratio) and the Sertoli cell index were used for quantitative traits. QTL analysis revealed two significant QTLs located on Chrs 1 and 11 for testis weight ratio and one significant QTL located in the same region of Chr 1 for the Sertoli cell index. A microsatellite marker locus located in the peak of the QTL on Chr 1 did not recombine with the exonuclease 1 (Exo1) gene locus in 140 F2 progenies. Mutation of the Exo1 gene was previously reported to be responsible for metaphase-specific apoptosis (MSA) of spermatocytes in the MRL/MpJ mouse. These results raise the possibility that mutation of the Exo1 gene is responsible for both MSA and heat stress resistance of spermatocytes in the MRL/MpJ mouse.
authors.affiliation: Laboratory of Experimental Animal Science, Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Namiki
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kon
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Kazusa
authors.forename: Atsushi
authors.initials: A
authors.lastname: Asano
authors.forename: Nobuya
authors.initials: N
authors.lastname: Sasaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Agui
mesh_terms: D000818:Animals; D003433:Crosses, Genetic; D005090:Exodeoxyribonucleases / Q000235:genetics*; D005838:Genotype; D018869:Heat-Shock Response / Q000235:genetics* / Q000502:physiology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D018895:Microsatellite Repeats / Q000235:genetics; D009154:Mutation / Q000235:genetics; D009929:Organ Size; D040641:Quantitative Trait Loci / Q000235:genetics*; D013090:Spermatocytes / Q000502:physiology*; D013737:Testis / Q000033:anatomy & histology
chemical_list: D005090:Exodeoxyribonucleases; C028450:exodeoxyribonuclease I