Esterase-23 (ES-23): Characterization of a new carboxylesterase isozyme (EC 3.1.1.1) of the house mouse,genetically linked to ES-2 on chromosome 8

Genetic variation of a carboxylesterase isozyme (EC 3.1.1.1) of the house mouse, designated ES-23, is described. ES-23 was found in kidney, liver, and intestine. The isozyme was resistant to inhibition by 10(-3) mol/liter eserine and was stained using alpha-naphthyl butyrate or 5-bromoindoxyl acetate as substrate. Five different phenotypes, ES-23A to ES-23E, could be distinguished by disc electrophoresis and by isoelectric focusing. ES-23 is controlled by a structural locus situated within the esterase gene cluster 2 on chromosome 8. An analysis of allele distribution among different strains suggested a separate structural locus for the isozyme, Es-23e, which is closely linked to the loci Es-2, Es-5, Es-7, and Es-11. Of the five phenotypes, only ES-23B was expressed in lung. This variation is apparently controlled by a cis-acting regulatory element, presumably a temporal locus, Es-23t, closely linked to the presumed structural locus Es-23e.     

Genetic characterization of esterase 28 (ES-28) of the house mouse

The genetics of esterase-28, the major esterase of cauda epididymidis of the house mouse, has been studied after separation by polyacrylamide gel electrophoresis and isoelectric focusing. Four phenotypes are distinguished. Segregation ofEs-28 in two backcross series indicated linkage to Es-1, Es-9, and Es-22. The Es-28 locus was placed into esterase cluster 1 on chromosome 8.This work was supported by the Deutsche Forschungsgemeinschaft.This is communication No. 69 of a research program devoted to the cellular distribution, genetics, and regulation of nonspecific esterases.     

Esterase-29 (ES-29): Biochemical characterization and control by two independent gene loci of a testosterone-dependent mouse serum esterase

Biochemistry and genetics of a testosterone-dependent murine serum esterase designated esterase-29 (ES-29) are described. The enzyme was identified after disc electrophoresis and subsequent staining for esterase using -naphthyl acetate as the substrate. It was inhibited by bis-p-nitrophenyl phosphate and was resistant top-chlorophenylsulphonate and hence was classified as carboxylesterase EC 3.1.1.1. The molecular mass was estimated to be about 130 kDa. It was shown that ES-29 is under the control of two independent genes. The first, termed Es-29, is suggested to be a structural locus, linked to the cluster-2 esterase loci on chromosome 8. Three alleles atEs-29, Es-29 ^a, Es-29^b, andEs-29 ^care distinguished, which determine absence (SEG/1), strong activity (BALB/cJ), and low activity (MOLH/Fre), respectively. The second locus, termedMse-1 (serum esterase modifying factor), was found to be closely linked toPre-2 on chromosome 12 and is suggested to be a modifying or regulatory gene. Two alleles were distinguished,Mse-1 ^a(BALB/cJ) andMse-1 ^m(MOL3/JA, CasBgr), which determine whether ES-29 appears as a single band or a double band, respectively.Mse-1 ^mis dominant toMse-1 ^a.This work was supported by the Deutsche Forschungsgemeinschaft. This is communication No. 70 of a research program devoted to the cellular distribution, genetics, and regulation of nonspecific esterases.     

Esterase-18 (ES-18) of the house mouse (Mus musculus): Biochemical characterization and genetics of an allozyme system linked to chromosome 19

This study describes the biochemical characterization, genetic variation, and linkage of a codominantly inherited murine esterase, termed ES-18. The enzyme was identified by isoelectric focusing of supernatants obtained after centrifugation of tissue homogenates and subsequent staining for esterase using either alpha-naphthyl acetate or 4-methylumbelliferyl elaidate as substrate. ES-18 exhibited an organ-specific variation of the intensity pattern of bands as seen in kidney, spleen, and macrophages, respectively. Its activity was highly sensitive to inhibition by 1 mmol.liter-1 p-chloromercuriphenylsulfonate but was resistant to bis-p-nitrophenyl phosphate. Four allozymes could be distinguished in kidney supernatants obtained from the inbred strains C57BL/10Sn (ES-18A), MOLF/Ei (ES-18B), WLL/BrA (ES-18C), and CAST/Ei (ES-18D). The enzyme is shown to be controlled by a structural locus, Es-18, which resides on chromosome 19. The gene order Ly-1 - Got-1 - 4.7 +/- 1.6 - Es-18 is suggested.     

Purine nucleoside phosphorylase (Np) in the mouse: Linkage relationship of Np-2 to esterase-10 (Es-10) and Np-1 on chromosome 14

An improved method for detecting four Np-1 (purine nucleoside phosphorylase) alleles in mouse erythrocytes by cellulose acetate electrophoresis is described. The previous linkage of Np-1 and Es-10 (esterase-10) was confirmed, with a map distance of 13.0±2.6 cM. Np-2 was detected by either specific activity assay or starch gel electrophoresis and shown to be linked to Es-10, 15.9 ± 3.1 cM, on chromosome 14. No recombinants between Np-1 and Np-2 were observed in 52 offspring, indicating either that these loci are either closely associated or that Np-2 represents simply a property of existing allelic products of the Np-1 locus.This research was supported by Medical Research Council of Canada grants to F.G.B. and F.F.S.     

Esterase-17 (ES-17): Characterization and genetic location on chromosome 9 of a bis-p-nitrophenyl phosphate-resistant esterase of the house mouse (Mus musculus)

Genetic variation of a new codominantly inherited esterase, designated ES-17, has been discovered in the house mouse using isoelectric focusing in polyacrylamide gels. The ES-17 A phenotype (three bands; isoelectric points, betweenpH 5.55 andpH 5.90) was found in C57 BL/10Sn. LP/J possessed the Es-17B phenotype (three bands; isoelectric points,pH 5.05–5.55). ES-17 was present in all tissues examined, except for hemolysate and serum, and was most clearly expressed in the small intestine. Because of its reaction toward various substrates and inhibitors, ES-17 has tentatively been classified as acetyl esterase (EC 3.1.1.6). ES-17 was shown to be controlled by the structural locusEs-17, located on chromosome 9. From test-cross data, a gene order ofEs-17-8.7±2.5 map units-Mpi-1-10.2±2.7 map units-Mod-1 was established. This work was supported by the Deutsche Forschungsgemeinschaft (SFB 46). This is communication No. 35 of a research program devoted to the cellular distribution and genetics of nonspecific esterases.     

Esterase-25(Es-25): Identification and characterization of a new kidney arylesterase of the house mouse,genetically linked toLy-18 on chromosome 12

Genetic variation of a codominantly inherited kidney esterase, designated ES-25, has been discovered in the house mouse using disc electrophoresis. The ES-25A phenotype was found in A strains, AKR, and BALB/c. ES-25B was found in C57BL strains and several other laboratory strains. The enzyme was shown to be controlled by a presumed structural locus, Es-25. The high concordance in 48 RI strains of Es-25 with Ly-18 indicated the location of Es-25 on chromosome 12. The gene order Es-25-Ly-18-D12Nyul-Pre-1 was proposed.     

Genetics and development of ocular oxidases in the mouse: evidence for a new locus (Eox-l) closely linked with the aldehyde oxidase loci on chromosome 1

Summary. Isoelectric focusing (IEF) and histochemical techniques were used to examine the genetics, postnatal development and biochemical properties of ocular oxidases (EOXs) among inbred strains of mice. The designation as EOX was made on a provisional basis, since the 'natural' substrate(s) for this enzyme have not been identified. Five major forms were resolved from adult animals, which exhibited high activity in murine lens and low activity in the cornea. An additional ocular oxidase was observed in neonatal animals. Genetic analyses demonstrated that one of these enzymes (EOX-1) is encoded by a locus (Eox-1) which is closely linked with, but distinct from, the aldehyde oxidase (Aox) gene complex on chromosome one of the mouse. These results support the proposal that ocular oxidases are distinct from the major liver AOXs in this organism.     

Esterase-26 (ES-26): Characterization and genetic location on chromosome 3 of an eserine-sensitive esterase of the house mouse (Mus musculus)

Genetic variation of a codominantly inherited esterase, designated ES-26, has been discovered in the house mouse using isoelectric focusing in polyacrylamide gels. The ES-26A phenotype (pI 8.2) was found in C57BL/10Sn. A/J showed the ES-26B phenotype (pI 7.8-7.9). A third phenotype, ES-26C (double-banded: pI's 8.1 and 8.3), was observed in SJL/J. ES-26 was detected only in liver, stomach, and small intestine. The enzyme was shown to be controlled by the presumed structural locus Es-26, located on chromosome 3. From a four-point cross, the gene order Car-2--6.2 +/- 2.7--Es-16--21.0 +/- 4.5--Es-26--13.6 +/- 3.8--Amy-1 was established.     

Aldehyde reductase isozymes in the mouse: Evidence for two new loci and localization of Ahr-3 on chromosome 7

Evidence is presented for two new forms of mouse liver and kidney aldehyde reductase activity (designated AHR-3 and AHR-4) resolved using cellulose acetate electrophoresis zymogram techniques and stained by glyceraldehyde and NADPH as substrate and coenzyme, respectively. Activity variants were observed for those isozymes among inbred strains of mice and used in a genetic analyses to support a proposal for two new genetic loci (Ahr-3 and Ah-4) which control the activity phenotype for these isozymes. Segregation analysis indicated that these loci are separately localized on the mouse genome, with Ahr-3 positioned on the distal end of chromosome 7. Liver AHR-2 (or hexonate dehydrogenase) exhibited no detectable phenotypic variation among the 44 inbred strains of mice examined. The AHR-3 and AHR-4 isozymes were readily distinguished from AHR-1 [or aldehyde reductase A₂, described previously by Duley and Holmes (Biochem. Genet. 20:1067, 1982)], hexonate dehydrogenase (AHR-2), and alcohol dehydrogenase A₂ in terms of their differential substrate, coenzyme, and inhibitor specificities.     

Biochemistry and genetics of esterase-20 (ES-20), a second trimeric carboxylesterase of the house mouse (Mus musculus). I. Purification and characterization of ES-20C1 from male kidney

ES-20 was isolated from male mouse kidney and purified 350-fold by ion-exchange chromatography, isoelectric focusing, and gel filtration. The resultant product was apparently homogeneous by the criteria of polyacrylamide gel electrophoresis and immunodiffusion and represented a major fraction of male mouse kidney esterase. Sodium dodecyl sulfate gel electrophoresis revealed the presence of a single subunit band, molecular weight 59,500; the molecular weight of the native protein was found to be 179,000. Titration of the active site yielded an equivalent weight of about 175,000. The enzyme was further characterized by its kinetic parameters for the hydrolysis of a series of 4-nitrophenyl esters and was classified as a carboxylesterase (EC 3.1.1.1). ES-20C1 bound to concanavalin A, indicating that it was a high-mannose-type glycoprotein; the role of terminal beta-N-acetylglucosamine residues in the carbohydrate side chains for stabilization of the quaternary structure of the trimer was revealed. Extensive biochemical and immunological similarities to ES-9C supported an earlier suggestion that the Es-9c gene product is a component of the ES-20C1 trimer.     

Mapping of the mouse bilirubin UDP-glucuronosyltransferase gene (Gnt-1) to chromosome 1 by restriction fragment length variations

Restriction endonuclease fragment length variations (RFLVs) were detected by using a rat cDNA probe for the bilirubin UDP-glucuronosyltransferase (UDPGT) gene between two mouse strains, 129/Sv and MOL-MIT. RFLVs of the gene were found byEcoRI andPvuII digestions. From linkage analyses of the three-point cross test usingElo andEn-1 as marker genes, the bilirubin UDPGT gene was mapped at position 37 on chromosome 1. Bilirubin and phenol UDPGTs have been suggested to be expressed by a single gene by alternative splicing in human and rat. The mouse bilirubin UDPGT gene was namedGnt-1.This study was supported by Grant-in-Aid for Research Project A-II from the Institute for Developmental Research, Aichi Prefecture Colony.     

Reproductive isolation between chromosomal races of the house mouse Mus musculus domesticus in a parapatric contact area revealed by an analysis of multiple unlinked loci

The house mouse, Mus musculus domesticus, exhibits a high level of chromosomal polymorphism because of the occurrence and fast fixation of Robertsonian fusions between telocentric chromosomes. For this reason, it has been considered a classical speciation model to analyse the role of the chromosomal changes in reproductive isolation. In this study, we analysed a parapatric contact area between two metacentric races in central Italy, the Cittaducale race (CD: 2n = 22) and the Ancarano race (ACR: 2n = 24), to estimate gene flow at the boundary. Hybrids between these two races show high levels of structural heterozygosity and are expected to be highly infertile. A sample of 88 mice from 14 sites was used. The mice were genotyped by means of eight microsatellite loci mapped in four different autosomal arms. The results show clear genetic differentiation between the CD and ACR races, as revealed by differences in allele frequencies, factorial correspondence analysis and indexes of genetic population (e.g. F(ST) and R(ST)) along the contact zone. The genetic differentiation between the races was further highlighted by assignation and clustering analyses, in which all the individuals were correctly assigned by their genotypes to the source chromosomal race. This result is particularly interesting in view of the absence of any geographical or ecological barrier in the parapatric contact zone, which occurs within a village. In these conditions, the observed genetic separation suggests an absence of gene flow between the races. The CD-ACR contact area is a rare example of a final stage of speciation between chromosomal races of rodents because of their chromosomal incompatibility.     

Provisional assignment of the gene for uridine monophosphatase-2 (Umph-2) to mouse chromosome 11

The segregation of the mouse gene for uridine monophosphatase-2 (Umph-2) was examined in 14 independent mouse-Syrian hamster hybrids and 10 hybrid subclones. Umph-2 cosegregated with the mouse galactokinase (Glk) gene in 23 of the 24 hybrids and showed at least four discordances with all other mouse marker isozymes examined. The observed synteny of Umph-2 and Glk, which has also been observed in humans, indicates that the mouse Umph-2 gene is on chromosome 11.     

Esterase-16 (Es-16): Characterization,polymorphism, and linkage to chromosome 3 of a kidney esterase locus of the house mouse

A polymorphism for an isozyme of a presumed arylesterase, esterase-16 (EC 3.1.1.2), has been detected in kidney, heart, and spleen of the house mouse, Mus musculus, by means of isoelectric focusing and by disc electrophoresis. Three phenotypes can be distinguished: the ES-16A phenotype (IEP 5.9) was found in C57BL/10Sn and many other laboratory inbred strains; the ES-16B phenotype (IEP 6.1) was found in M. m. molossinus; and the ES-16C phenotype (IEP 5.9; very weak activity) was found in Peru-Coppock. Esterase-16 is strongly inhibited by 10^?3 m p-chloromercuribenzoate, but not by 2·10^?4 m bis-p-nitrophenyl phosphate or by 10^?3 m Diamox. It stains well with indoxyl acetate and other indigogenic substrates but only weakly with α-naphthyl acetate. Esterase-16 is completely insoluble in water. It is apparently governed by a structural gene locus, Es-16, with three alleles, Es-16 ^a , Es-16^b, and Es-16 ^c, respectively. Es-16 is closely linked to Car-1 and Car-2 on chromosome 3. Typing of 94 animals of the backcross (C57BL/10Sn × M. m. mol.) F₁ × M. m. mol. revealed a recombination frequency of 8.51±2.9%.     

Genetics of formamidase-5 (brain formamidase) in the mouse: Localization of the structural gene on chromosome 14

A single formamidase, which is different from the formamidases found in other tissues, occurs in the brains of mice. This enzyme is here called formamidase-5 and the gene symbol is designated For-5. Two alleles are recognized on the basis of their differential heat sensitivity: For-5 ^b is relatively heat stable and is present in strain C57BL/6J, while For-5 ^d is relatively heat sensitive and is present in strain DBA/2J. The heat sensitivity of formamidase-5 in 44 other inbred strains and substrains was tested and found to resemble that of C57BL/6J or DBA/2J. Thirty-six recombinant inbred strains derived from progenitors that differed at For-5 were studied to test for single-gene inheritance and linkage with other loci. Complete concordance was found with the esterase-10 locus (Es-10), indicating close linkage. The 99% upper confidence limit of the distance between For-5 and Es-10 is 3.7 centimorgans (cM). Es-10 is located on chromosome 14 about 19 cM from the centromere. An independent demonstration of linkage of For-5 with Es-10 and another chromosome 14 marker, hairless (hr), is provided by the finding that the HRS/J strain, which has been sibmated for 60 generations with forced heterozygosity at the hr locus, is cosegregating at For-5 and Es-10. A survey of 32 inbred strains and substrains revealed that the For-5 ^d allele is associated with the Es-10 ^b allele, and that the For-5 ^b allele is associated with Es-10 ^a and Es-10 ^c. Formamidase-5 segregates as expected in the F₂ generation of crosses between strains bearing For-5 ^b and For-5 ^d alleles. It is possible that this unique formamidase of the brain is involved in the metabolism of a neurotransmitter substance.This research was sponsored in part by the Department of Energy under contract with the Union Carbide Corporation and in part by NIH Research Grant GM-18684 from the National Institute of General Medical Sciences. J. C. F. is a predoctoral Fellow supported by Grant CA 09104 from the National Cancer Institute. The Biology Division of Oak Ridge National Laboratory and the Jackson Laboratory are fully accredited by the American Association for Accreditation of Laboratory Animal Care.     

Aneuploidy in metaphases II of spermatocytes of wild house mice from a hybrid zone between a Robertsonian population (CD: 2n = 22) and a population with the standard karyotype (2n = 40)

Meiotic metaphases II from archival slides were studied of male house mice caught in a hybrid zone between a population monomorphic for nine centric fusions (2n = 22) and a population with the standard karyotype (2n = 40), near Rome. The frequency of aneuploidy increases, up to 50%, with increasing number of heterozygous centric fusions (1–4). This revised version was published online in July 2006 with corrections to the Cover Date.     

Genetic variation and biochemical properties of esterase-18 (ES-18) in the laboratory rat (Rattus norvegicus): A new locus of esterase cluster 2 in linkage group V

A new liver-specific rat carboxylesterase isozyme (EC 3.1.1.1) designated esterase-18 (ES-18) is described. Genetic variation of ES-18 was examined in 93 inbred strains and substrains and a structural locusEs-18 was suggested, coding for either the presence (Es-18 ^a) or the absence (Es-18 ^b) of the isozyme. Linkage studies involving two backcross series revealed thatEs-18 resides in cluster 2 of LGV. No recombination betweenEs-18 and other cluster 2 loci was found in 19 lines of two RI strain sets or in the backcross series.R. K. was supported by the Sonderforschungsbereich 146 (Versuchstierforschung). O.D. was supported by the Deutsche Forschungsgemeinschaft (De 315/2). This is communication No. 65 of a research program devoted to the cellular distribution, regulation, and genetics of nonspecific esterases.     

Chromosomal dynamics of nucleolar organizer regions (NORs) in the house mouse: micro-evolutionary insights

Variation in the number and chromosomal location of nucleolar organizer regions (NORs) was studied in the house mouse, Mus musculus (2n=40). From an origin in Western Asia, this species colonized the Middle East, Europe and Asia. This expansion was accompanied by diversification into five subspecies. NOR diversity was revealed by fluorescence in situ hybridization using 18S and 28S probes on specimens spanning Asia to Western Europe. The results showed that the house mouse genome possessed a large number of NOR-bearing autosomes and a surprisingly high rate of polymorphism for the presence/absence of rRNA genes on all these chromosomes. All NOR sites were adjacent to the centromere except for two that were telomeric. Subspecific differentiation established from the NOR frequency data was concordant with the overall pattern of radiation proposed from molecular studies, but highlighted several discrepancies that need to be further addressed. NOR diversity in M. musculus consisted of a large number of polymorphic NORs that were common to at least two subspecies, and a smaller number of NORs that were unique to one subspecies. The most parsimonious scenario argues in favor of a subspecific differentiation by lineage sorting of ancestral NOR polymorphisms; only the unique NORs would have appeared by inter-chromosomal transposition, except for the two telomeric ones that may have originated by hybridization with another species. Such a scenario provides an alternative view from the one prevailing in most systematic and phylogenetic analyses that NORs have a high transposition rate due to concerted evolution of rRNA genes.