Mapping of theEs-4 locus and linear order of esterase genes (linkage group V; LGV) in the rat

There are three different linear orders of esterase loci of linkage group V (LGV) in the rat (Rattus norvegicus). The first is Es-2-Es-3-Es-1, the second Es-3-(Es-2,Es-4)-Es-1, and the third Es-3-Es-2-Es-1-Es-4. We carried out mating experiments to define the order clearly. Linkage analyses of the four esterase loci, Es-1, Es-2, Es-3, and Es-4, were carried out using two inbred strains carrying different alleles at the four loci. Six locus combinations examined in this study were as follows: Es-1-Es-2, Es-1-Es-3, Es-1-Es-4, Es-2-Es-3, Es-2-Es-4, and Es-3-Es-4. The recombination frequencies of each combination were 6.3, 6.3, 6.3, 5.2, 1.8, and 3.4%, respectively. The first recombination between Es-2 and Es-4 was observed. We propose that the esterase loci of LGV be classified into three clusters according to distances between the loci. The linear order of the four loci is shown to be as follows: [Es-3] (cluster II)-3.4 +/- 2.4%-[Es-4-1.8 +/- 1.7%-Es-2] (cluster III)-6.3 +/- 6.1%-[Es-1] (cluster I).     

Linkage analyses among five esterase loci in the laboratory rat (Rattus norvegicus)

A cluster of esterase loci has been identified on a segment of a rat linkage group V; however, the linear order of all the loci has not been established. We estimated the recombination frequencies of two locus combinations among five esterase loci (Es-1, Es-2, Es-3, Es-4, and Es-Si) and the linear order of the loci by using three sets of backcross matings: (1) (K:W × IS) × IS, (2) (K:W × IS) × IS, and (3) (SHR × W) × W). The linear order was determined to be Es-1-Es-4-Es-2-Es-3-Es-Si, although the order of Es-2 and Es-4 remains tentative. The sexinfluenced esterase (Es-Si) was demonstrated to be distinct from Es-1 and was proposed to be Es-Si locus with two alleles of Es-Si ^a (positive) and Es-Si ^b (null).This work was partly supported by Grants-in-Aid for Scientific Research, No. 339020 (1978), from the Ministry of Education, Science and Culture, Japan.     

Esterase-6 (Es-6) in laboratory mice: Hormone-influenced expression and linkage relationship to oligosyndactylism (Os), esterase-1 (Es-1), and esterase-2 (Es-2) in chromosome 8

Allelic differences at an esterase locus designated Es-6 exist between mouse strain C57 BL/6J and a laboratory stock of M.m. molossinus. Strain C57BL/6J has been assigned the allele Es-6a and M. m. molossinus the alternate allele Es-6b. Kidney expression of the electrophoretic esterase band controlled by the Es-6 locus is sex influenced, with increased activity apparently induced by testosterone. A four-point test cross established the gene order Os-Es-1-Es-6-Es-2 within a 10-cM segment on chromosome 8.     

Esterase-16 (ES-16) of the rat (Rattus norvegicus): Identification and genetic characterization

Esterase-16, an esterase present in lung and other tissues of the laboratory rat, has been characterized by its biochemical properties (electrophoretic mobility, substrate pattern, sensitivity to inhibitors) and genetic variation in 107 inbred strains and substrains including 14 RI strains. It was classified as a carboxylesterase (EC 3.1.1.1). The phenotype ES-16A (BN/Han and 63 other strains) was defined as a narrow electrophoretic band migrating between ES-1A and ES-13A, ES-16B (LEW/Han and 42 other strains) exhibited the same electrophoretic mobility as ES-16A but was distinguished by its extremely weak activity. Segregation of ES-16 in RI strains and backcrosses indicated linkage to linkage group V (LGV). The Es-16 locus was tentatively placed into esterase cluster 2 and homology with Es-7 of the house mouse is proposed.     

Re-evaluation of LG V of the rat and assignment of 12 carboxylesterases to two gene clusters

Examining the strain distribution pattern of the recombinant inbred strain series LXB and DXE and of backcross progeny of (LEW X LE)F1 X LEW, (LEW X BN)F1 X LEW, and (LEW X BN)F1 X BN for esterase markers, including three carboxylesterase allozymes (ES-15, ES-16, ES-18), hitherto not studied genetically, revealed the existence of two esterase gene clusters within LG V: cluster 1, containing Es-2, Es-8, Es-10, Es-3, Es-7, Es-9, and separated by 8.8 +/- 1.3 cM from cluster 2, containing Es-1, Es-14 (formerly Es-Si), Es-15, Es-16, and Es-18. Analyses of 93 inbred strains of rats showed only 12 and 6 haplotypes for cluster 1 and cluster 2, respectively, indicating a strong linkage disequilibrium. These data and serotyping results of one backcross population for the RT2 blood group system lead to a re-evaluation of linkage group V. Including literature data the following gene order is suggested: RT2 - (7.1 +/- 1.8) Es-2, Es-4, Es-8, Es-10 (2.7 +/- 0.7) Es-3, Es-7, Es-9 (8.8 +/- 1.3) Es-1, Es-14, Es-15, Es-16, Es-18.     

Gene mapping on mouse chromosome 8 by interspecific crosses: new data on a linkage group conserved on human chromosome 16q

A large conserved linkage group exists on mouse chromosome 8 and human chromosome 16q, including the loci for chymotrypsinogen B (Ctrb), haptoglobin (Hp), lecithin:cholesterol acyltransferase (Lcat), metallothionein-1,-2 (Mt-1,-2), tyrosine aminotransferase (Tat), and uvomorulin (Um). Using cloned gene probes, these six loci were mapped in M. m. domesticus X M. spretus interspecific crosses relative to a number of chromosome 8 anchor loci resulting in the gene order Es-1,Es-9-Mt-1,-2-Got-2-Es-2,Es-7,Lcat,Um-Hp,Tat,Ctrb-e. These results complement earlier studies and redefine the conserved segment on mouse chromosome 8, previously defined by the Hp-Tat interval, by the 24-cM interval between Mt-1,-2 and the conserved locus for adenine phosphoribosyltransferase, Aprt, mapped at 25 cM from Es-1 by T. B. Nesterova, P. M. Borodin, S. M. Zakian, and O. L. Serov (1987, Biochem. Genet. 25: 563-568). Within this segment, the gene order appears the same in man and mouse. While map distances between HP-TAT,HP-CTRB, and TAT-CTRB of respectively 7, 11, and 9 cM have previously been measured in man, no crossovers between Hp, Tat, and Ctrb were observed in over 100 meioses in the mouse.     

Es-6, a further polymorphic esterase in the rat

A further polymorphic rat esterase with broad tissue expression and restricted substrate specificity is described and tentatively called Es-6. Inbred rat strains have either fixed allele Es-6^F or fixed allele Es-6^S. Es-6 is not linked to the established esterase cluster consisting of the eight esterase loci Es-1, Es-2, Es-3M, Es-4M, Es-4W, Es-5 (=Es-3W), Es-7, and Es-8 in LG V of the rat or to RT1, Gc, c, a, and h. Esterases with apparently identical biochemical and genetical characteristics are Es-17 of the mouse and Es-A4 of humans.Supported by the Deutsche Forschungsgemeinschaft (Be 352/13 and Gu 105).     

Biochemical and genetic characterization of esterase-27 (ES-27), the major plasma cholinesterase of the house mouse (Mus musculus)

Esterase-27A (ES-27A) was characterized in strain A/WySnA by a cascade of seven bands seen after disc electrophoresis of serum and subsequent staining for esterase. ES-27A catalyses the hydrolysis of thiocholine butyrate and is strongly inhibited by 100 microM tetraisopropyl pyrophosphamide (isoOMPA). Hence, the enzyme was concluded to be a cholinesterase EC 3.1.1.8. A heat-labile form termed ES-27B was represented by strain AKR/Han. From a three-point cross (AKR/Han, A/Wy) and a five-point cross (AKR/Han, SEG/1), the gene order on chromosome 3 was concluded to be centromere-Car-2-Es-26-Es-27-Amy-1-Adh-1.     

Biochemistry and genetics of esterase-20 (ES-20), a second trimeric carboxylesterase of the house mouse (mus musculus). II. A unique recombination reveals ES-20 as a hybrid enzyme

A unique recombination is described between (Es-1, Es-6) and (Es-9, Es-22) within gene cluster 1 of the esterase gene region on chromosome 8 of the house mouse. This recombination established the gene order Es-1--Es-6--(Es-9, Es-22)--Got-2. A further 73 recombinations, from a total of 911 backcrosses, had taken place between cluster 1 and cluster 2. A distance between the clusters of 8.01 +/- 0.90% was calculated; the genes within the clusters appeared more tightly linked than previously assumed. ES-20 behaved anomalously following the recombination within cluster 1: homozygous descendants of the recombinant expressed a new form of ES-20. In vitro incubation of purified ES-6A3 and ES-9A generated ES-20A, revealing this esterase to be a hybrid of different cluster 1 gene products, Es-9 and possibly Es-6. This result satisfactorily accounted for the genetic finding, as well as a range of biochemical properties of ES-20.     

Heterogeneity of Es-1 esterases in the rabbit (Oryctolagus cuniculus)

Analysis of the Es-1 system in the rabbit with polyacrylamide gel electrophoresis (PAGE) revealed a high degree of individual variation. In the liver the number of esterase bands found in the Es-1 region of the gels ranged from 2 to 16. The results indicate that one locus with three alleles is responsible for all of the esterase bands in the Es-1 region. The most plausible explanation for the observed heterogeneity is that each of the alleles codes for a protein (MW 65,000±2000) that is changed by posttranslational modifications, thus giving rise to two to five monomeric enzymes with esterase activity. Polymerization of these monomers then results in 1–11 dimers. Based on similarities with mouse Es-9, chromosomal homology between rabbit Es-1 and mouse Es-9 is proposed.     

Mapping of nucleoside phosphorylase (Np-1) and esterase 10 (Es-10) on mouse chromosome 14

A method for detecting two alleles at Np-1 (nucleoside phosphorylase) and three alleles at Es-10 (esterase 10) from mouse blood by cellulose acetate electrophoresis is described. The allelic constitution at these loci for 44 inbred strains and stocks was determined. The location of Np-1 on chromosome 14 was established by backcross experiments in which alleles at Np-1 and Robertsonian translocations were segregating. Es-10 was shown to be linked to Np-1, and the following genetic map of Chr 14 was constructed: centromere-(8.9±4.0 cM)-[Np-1, Wc]-(10.2±1.9 cM)-Es-10-(15.5±3.7 cM)-s. The homologous human loci, NP and ES-D, are not linked.This work was supported by Contract E(11-1)-3267 with the Energy Research and Development Administration, by Contracts NO1-ES4-2156 and NO1-ES4-2159 with the National Institute of Environmental Health Sciences, and by Grants GM 19656 and GM 20919 from the National Institute of General Medical Sciences. D. A. K. was a participant in the 1975 Summer Program for College, Graduate, and Medical Students, which was supported, in part, by the Clark Foundation. The Jackson Laboratory is fully accredited by the American Association for Accreditation of Laboratory Animal Care.     

A new variant of the Es-4 locus in the rat

A new variant of kidney esterase in the DK/Nac rat strain is reported. The new esterase was tentatively named ES-4C determined by a third allele of the Es-4 locus of Linkage Group V (LGV). Strain distribution was surveyed using 17 inbred strains, but no strain except for the DK/Nac strain possessed the ES-4C type. Although we surveyed outbred stocks (Jcl: Wistar and Jcl: SD) we could not find rats carrying the ES-4C type. Genetic analysis of the ES-4C type was carried out using mating experiments between DK/Nac and BUF/Nac (ES-4B). The results indicated that the new variant was controlled by the Es-4 locus and it was named the Es-4c allele.     

Esterase-7, a common constituent of numerous mouse tissues.

1. Electrophoretic and staining techniques for the relatively specific demonstration of esterase-7 in mouse tissues are described. Esterase-7 was found to be a common constituent of most mouse tissues. 2. The electrophoretic polymorphisms determined by three alleles a, b and c were studied in nine mouse strains. 3. The banding pattern of esterase-7 is being described and the isoelectric points of the allelic bands are being estimated. 4. Recombination studies on a further 129 animals confirmed that the Es-7 locus is tightly linked to Es-2 and Es-11. 5. Esterase-7 precipitates with antiesterase-2 from the rabbit. 6. It differs from esterase-2 by its individual substrate preference and by its susceptibility to inhibition by acylating agents.     

A new polymorphic pepsinogen locus (Pg-2) in the rat (Rattus norvegicus)

Only two types of pepsinogens, which are products of the Pg-1 locus, are present in rat urine. In gastric mucosa, however, additional pepsinogen isozymes are expressed. We have found a polymorphism for rat gastric mucosa pepsinogen using agarose gel electrophoresis. Some inbred rat strains expressed a pepsinogen band, while others did not. The trait was found to be controlled by a single autosomal locus. We tentatively designated the locus as Pg-2 with two alleles, Pg-2a for the one controlling presence of the band and Pg-2o for the one controlling absence. Linkage analysis using BN and TM strains revealed that Pg-2 was closely linked to Pg-1 (3.7 +/- 1.8 cM), and that it did not belong to LG I (Hbb and p), LG II (Acon-1 and Mup-1), LG IV (Hao-1 and Svp-1), LG V (Es-1 and Es-3), LG VI (Gc and h), LG IX (RT1), LG X (Fh and Pep-3), nor a LG containing Ahd-2 (as yet undetermined).     

Biochemical genetics of rat esterases: Polymorphism,tissue expression,and linkage of four loci

Two alleles at each of four esterase loci in Rattus norvegicus are described with regard to tissue expression, electrophoretic characterization, and genetic linkage. A previously described dominant gene for prealbumin serum esterase is demonstrated to exist as two codominant alleles in the genetically determined absence of the characteristic albumin esterase. The allelic composition of 16 inbred strains for four esterase genes is provided, and the heretofore ambiguous nomenclature of rat esterase genetics is standardized. Linkage of Es-1, Es-2, and Es-3 is demonstrated. Es-2 and Es-3 are tightly linked in that no recombination has been observed in 55 offspring. The same offspring demonstrated 9% recombination between Es-1 and the other two loci.This work was supported by a grant from the Brown-Hazen Fund of Research Corporation.     

The murine retinoblastoma homolog maps to chromosome 14 near Es-10

Restriction fragment length variants have been exploited to map genetically Rb-1, the murine homolog of the human retinoblastoma gene. Rb-1 localized to mouse chromosome 14 on the basis of results from analysis of somatic cell hybrids. In an interspecific backcross involving Mus spretus, Rb-1 and the murine homolog of the human esterase D gene (ESD), which we refer to here as Esd, were inseparable. Furthermore, the strain distribution patterns of Rb-1 and Es-10 are the same in 31 of 32 recombinant inbred strains. Close linkage of the chromosome 14 morphological marker hairless (hr) to Rb-1 is also implied. These results localize Rb-1 on the mouse linkage map and provide close genetic markers to follow Rb-1 in somatic as well as in germline genetic experiments. Additionally, the results suggest that Es-10 is the murine homolog of ESD and provide further evidence for linkage conservation during mammalian evolution.     

Re-localization of Actsk-1 to mouse Chromosome 8, a new region of homology with human Chromosome 1

We present here the genetic mapping of the -skeletal actin locus (Actsk-1) on mouse Chromosome (Chr) 8, on the basis of the PCR analysis of a microsatellite in an interspecific backcross. Linkage and genetic distances were established for four loci by analysis of 192 (or 222) meiotic events and indicated the following gene order: (centromere)-Es-1-11.7 cM-Tat-8.3 cM-Actsk-1-0.5 cM-Aprt. Mapping of ACTSK to human Chr 1 and of TAT and APRT to human Chr 16 demonstrates the existence of a new short region of homology between mouse Chr 8 and human Chr 1. Intermingling on this scale between human and mouse chromosomal homologies that occurred during evolution creates disorders in comparative linkage studies.     

Serum esterase genetics: Identification and hormone induction of the Es-1b esterase in inbred rats

A previously unrecognized esterase from the sera of the appropriate strains of the rat Rattus norvegicus was revealed by a discontinuous polyacrylamide gel electrophoretic technique. This esterase migrated in the albumin region, whereas a previously known major albumin esterase controlled by the Es-2 locus migrated in the postalbumin region when the method was used. The new albumin esterase component which separated from the Es-2 esterase was identified as the product of the Es-1b gene. The new albumin esterase was not detectable in the sera of sexually mature males of the appropriate genotype, because the activity level of this esterase was influenced by sex hormones, especially androgen.     

Linkage of Nat and Es-1 in the mouse and development of strains congenic for N-acetyltransferase

The human polymorphism in the hepatic enzyme N-acetyltransferase (NAT) affects the rate at which individuals acetylate, and in many cases detoxify, aromatic amine and hydrazine drugs and xenobiotics. Differences in NAT activity are known to affect individual susceptibility to drug toxicities and are thought to play a part in some spontaneous disorders. A mouse model for the human acetylation polymorphism has been previously characterized and involves the A/J (slow acetylator) and C57BL/6J (rapid acetylator) inbred strains. Strain distribution analysis of 40 A x B and B x A recombinant inbred (RI) strains indicated linkage between the N-acetyltransferase gene (Nat) and the esterase 1 (Es-1) gene, located on mouse chromosome 8. A double backcross involving 107 animals confirmed the recombination frequency between Nat and Es-1 to be 12 +/- 3% (mean +/- SE). The information obtained in the backcross and RI studies was combined, yielding a 13 +/- 2.8% (mean +/- SD) recombination frequency. The Es-1 genotype was determined in our newly developed congenic strains A.B6-Natr and B6.A-Nats. The B6.A-Nats strain has the Es-1 genotype of its inbred partner, the B6 strain, and the A.B6-Natr strain has the Es-1 genotype of the donor strain. These congenic strains will be important in determining the role of the NAT genotype in susceptibility to arylamine-induced cancer and other disorders.     

The genetics of esterase 12 and esterase 13 polymorphisms in the Norway rat

2 new esterase polymorphisms (Es-12 and Es-13) were discovered in haemolysates of wild rats (Rattus norvegicus) by gel electrophoresis. Both loci are probably monomeric. Linkage analysis indicates that neither locus is associated with the esterase cluster in linkage group V.