Genetic analysis of barrel field size in the first somatosensory area (SI) in inbred and recombinant inbred strains of mice

We measured the combined area of posterior medial barrel subfield (PMBSF) and anterior lateral barrel subfield (ALBSF) areas in four common inbred strains (C3H/HeJ, A?/J, C57BL?/6J, DBA/2J), B6D2F1, and ten recombinant inbred (RI) strains generated from C57BL/6J and DBA/2J progenitors (BXD) as an initial attempt to examine the genetic influences underlying natural variation in barrel field size in adult mice. These two subfields are associated with the representation of the whisker pad and sinus hairs on the contralateral face. Using cytochrome oxidase labeling to visualize the barrel field, we measured the size of the combined subfields in each mouse strain. We also measured body weight and brain weight in each strain. We report that DBA/2J mice have a larger combined PMBSF/ALBSF area (6.15?±?0.10?mm²,?n?=?7) than C57BL?/6J (5.48?±?0.13?mm²,?n?=?10), C3H/HeJ (5.37?±?0.16?mm²,?n?=?10), and A/J mice (5.04?±?0.09?mm²,?n?=?15), despite the fact that DBA/2J mice have smaller average brain and body sizes. This finding may reflect dissociation between systems that control brain size with those that regulate barrel field area. In addition, BXD strains (average n?=?4) and parental strains showed considerable and continuous variation in PMBSF/ALBSF area, suggesting that this trait is polygenic. Furthermore, brain, body, and cortex weights have heritable differences between inbred strains and among BXD strains. PMBSF/ALBSF pattern appears similar among inbred and BXD strains, suggesting that somatosensory patterning reflects a common plan of organization. This data is an important first step in the quantitative genetic analysis of the parcellation of neocortex into diverse cytoarchitectonic zones that vary widely within and between species, and in identifying the genetic factors underlying barrel field size using quantitative trait locus (QTL) analyses.     

Spontaneous mutations in recombinant inbred mice: mutant toll-like receptor 4 (Tlr4) in BXD29 mice

Recombinant inbred (RI) mice are frequently used to identify QTL that underlie differences in measurable phenotypes between two inbred strains of mice. Here we show that one RI strain, C57BL/6J x DBA/2J (BXD29), does not develop an inflammatory response following inhalation of LPS. Approximately 25% of F2 mice [F1(BXD29 x DBA/2J) x F1] are also unresponsive to inhaled LPS, suggesting the presence of a recessive mutation in the BXD29 strain. A genomic scan of these F2 mice revealed that unresponsive animals, but not responsive animals, are homozygous for C57BL/6J DNA at a single locus on chromosome 4 close to the genomic location of Tlr4. All progeny between BXD29 and gene-targeted Tlr4-deficient mice are unresponsive to inhaled LPS, suggesting that the mutation in the BXD29 strain is allelic with Tlr4. Moreover, the intact Tlr4 receptor is not displayed on the cell surface of BXD29 macrophages. Finally, a molecular analysis of the Tlr4 gene in BXD29 mice revealed that it is interrupted by a large insertion of repetitive DNA. These findings explain the unresponsiveness of BXD29 mice to LPS and suggest that data from BXD29 mice should not be included when using BXD mice to study phenotypes affected by Tlr4 function. Our results also suggest that the frequency of such unidentified, spontaneously occurring mutations is an issue that should be considered when RI strains are used to identify QTL.     

Segregation patterns of endogenous mouse mammary tumor viruses in five recombinant inbred strain sets.

We identified mouse mammary tumor proviral loci in the AKR/J, C3H/HeJ, C57BL/6J, C57L/J, DBA/2J, and SWR/J inbred mouse strains and determined their segregation patterns in the AKXD, AKXL, BXD, BXH, and SWXL recombinant inbred strain sets. Two new Mtv loci, Mtv-29 and Mtv-30, were identified. Mtv-30 was genetically mapped to chromosome 12. Additionally, two previously identified Mtv loci, Mtv-14 and Mtv-23, were genetically mapped to chromosome 4 and chromosome 6, respectively.     

Mapping of theLyb-4 gene to different chromosomes in DBA/2J and C3H/HeJ mice

Linkage has been established between the Lyb-4 alloantigen locus and the chromosome 4 markersLyb- 2 andMup- 1 using recombinant inbred (RI) strains. Only 2 of 24 BXD RI strains possess recombinant genotypes with respect to the B cell alloantigen lociLyb- 4 andLyb- 2, for an estimated recombination frequency of 0.024 ±0.019. One additional BXD RI strain was a recombinant with respect toLyb- 4 andMup- 1 (major urinary protein locus) for an estimated recombination frequency of 0.039 ± 0.026. These linkages were confirmed and further quantitated in a (C57BL/6J × DBA/2J)F₁ × C57BL/6J backcross population, in which the recombination frequency betweenLyb- 4 andMup- 1 was 0.049 ± 0.019. No recombination between the expression of Lyb-4.1 antigen and the ability of anti-Lyb-4.1 serum to suppress MLC reactivity was found, indicating that the genes controlling the antigenic determinant which is recognized with cytotoxic antibodies in anti-Lyb-4.1 serum is the same as, or is very closely linked to, the gene which is responsible for augmentation of the MLC response. In contrast, no linkage was observed between the gene controlling the Lyb-4.1 determinant andMup- 1 in RI strain and backcross mice derived from the cross of C3H/HeJ and C57BL/6J. Again, there was complete concordance between the serologically recognized determinant and the ability of anti-Lyb-4.1 serum to suppress the MLC response. Absorption of anti-Lyb-4.1 serum with C3H/HeJ, DBA/2J, and C57BL/6J lymphocytes, followed by the cytotoxic assay of the absorbed sera on lymphocytes of each of these three strains showed that serologically the Lyb-4.1 antigenic determinant on DBA/2 mice was indistinguishable from that on C3H/HeJ mice. Thus, both traits appear to be under the control of single genes in both DBA/2J and C3H/HeJ, but the C3H/HeJ gene appears to be nonallelic and unlinked to the DBA/2J gene.Abbreviations used in this paper LAD lymphocyte activating determinants - LPS lipopolysaccharide - MLC mixed lymphocyte culture - RI recombinant inbred     

NaCl taste thresholds in 13 inbred mouse strains

Molecular mechanisms of salty taste in mammals are not completely understood. We use genetic approaches to study these mechanisms. Previously, we developed a high-throughput procedure to measure NaCl taste thresholds, which involves conditioning mice to avoid LiCl and then examining avoidance of NaCl solutions presented in 48-h 2-bottle preference tests. Using this procedure, we measured NaCl taste thresholds of mice from 13 genealogically divergent inbred stains: 129P3/J, A/J, BALB/cByJ, C3H/HeJ, C57BL/6ByJ, C57BL/6J, CBA/J, CE/J, DBA/2J, FVB/NJ, NZB/BlNJ, PWK/PhJ, and SJL/J. We found substantial strain variation in NaCl taste thresholds: mice from the A/J and 129P3/J strains had high thresholds (were less sensitive), whereas mice from the BALB/cByJ, C57BL/6J, C57BL/6ByJ, CE/J, DBA/2J, NZB/BINJ, and SJL/J had low thresholds (were more sensitive). NaCl taste thresholds measured in this study did not significantly correlate with NaCl preferences or amiloride sensitivity of chorda tympani nerve responses to NaCl determined in the same strains in other studies. To examine whether strain differences in NaCl taste thresholds could have been affected by variation in learning ability or sensitivity to toxic effects of LiCl, we used the same method to measure citric acid taste thresholds in 4 inbred strains with large differences in NaCl taste thresholds but similar acid sensitivity in preference tests (129P3/J, A/J, C57BL/6J, and DBA/2J). Citric acid taste thresholds were similar in these 4 strains. This suggests that our technique measures taste quality-specific thresholds that are likely to represent differences in peripheral taste responsiveness. The strain differences in NaCl taste sensitivity found in this study provide a basis for genetic analysis of this phenotype.     

The murine aromatic hydrocarbon responsiveness locus: a comparison of receptor levels and several inducible enzyme activities among recombinant inbred lines

The aromatic hydrocarbon responsiveness (Ah) locus has been correlated with genetic differences in the risk of drug toxicity, teratogenesis, chemical carcinogenesis, and mutagenesis. Hepatic cytosolic Ah receptor levels, 2-amino-5-chlorobenzoxazole (zoxazolamine) paralysis time following beta-naphthoflavone treatment and aryl hydrocarbon hydroxylase (AHH3, acetanilide 4-hydroxylase (Ac4H), and NAD(P)H:menadione oxidoreductase (NMOR)4, induction by 3-methylcholanthrene were studied in (a) the progenitors C57BL/6J (Ahb/Ahb) and DBA/2J (Ahd/Ahd) and 25 BXD recombinant inbred lines, (b) the progenitors C57BL/6N and C3H/HeN and 14 B6NXC3N recombinant inbred lines, and (c) the progenitors C57BL/6J and C3H/HeJ and 12 BXH recombinant inbred lines. The Ahb phenotype exhibits greater than 5 femtomole receptor/mg of cytosolic protein, less than or equal to 15 minutes zoxazolamine paralysis time, and twofold to 15-fold induction of these three hepatic enzyme activities; the Ahd phenotype exhibits less than or equal to 2 fmol receptor/mg protein, greater than 15 minutes zoxazolamine paralysis time, and less than 30% induction of these three activities. Among the BXD lines but especially among the B6NXC3N and BXH lines, high frequencies of recombination were found; the phenotype of each of the five parameters did not segregate with the phenotype of each of the other parameters in four or more recombinant lines. This report shows for the first time that AHH induction by 3-methylcholanthrene can occur in the Ahd phenotype mouse. These data underline the complexity of this genetic system when genes from C57BL/6 and DBA/2 are combined and particularly when genes from C57BL/6 and C3H/He inbred mouse strains are combined.     

Random sequence oligonucleotide primers detect polymorphic DNA products which segregate in inbred strains of mice

The random amplification of polymorphic DNA (RAPD) using primers of arbitrary nucleotide sequence has been extremely valuable in identifying heritable markers in a variety of systems. The present studies examined whether the RAPD technique can identify large numbers of polymorphisms that can be used to construct genetic maps in inbred strains of mice. By screening the inbred mouse strains C57BL/6J and DBA/2J with 481 random 10-mer oligonucleotide primers, we identified 95 polymorphisms and mapped 76 of these by use of the BXD series of recombinant inbred (RI) strains. The results clearly demonstrate that the RAPD technique allows for the identification of large numbers of DNA-based polymorphisms that distinguish these two inbred strains of mice,and that such markers can readily be used to construct molecular genetic linkage maps.     

Cryptosporidium infections in inbred strains of mice.

Cryptosporidium, a protozoan parasite of man and animals, is an important etiological agent of diarrhea throughout the world, particularly in children and immunocompromised individuals such as AIDS patients. Unfortunately, because of the lack of both in vivo laboratory models and reliable in vitro parasite culture systems, virtually nothing is known about the immunological events occurring during disease. In order to identify reliable animal models for infection, we studied C. parvum infections in 19 different strains of mice representing 12 H-2 haplotypes: A/J, AKR/J, B10.D2/J, B10.M/J, C3H/HeJ, C57BL/65, C57BL/6J-bgJ, CBA/NJ, DBA/1J, DBA/2J, HRS/J, HTG/J, NZB/B1NJ, NZW/J, P/J, RIII/J, SJL/J, SWR/J, and WB/ReJ, and in one gerbil: Meriones unguiculatus. Fecal samples and histological sections of the intestine taken on day 7 post-Cryptosporidium inoculation indicated that only the beige mouse (C57BL/6J-bgJ) harbored significant numbers of parasites compared to the other strains. The numbers of parasites harbored in these NK cell-deficient beige mice were, however, considerably lower than those seen in neonatal mice. Adult inbred mouse strains susceptible to Cryptosporidium infections are discussed.     

Genetic analysis of tongue size and taste papillae number and size in recombinant inbred strains of mice

Quantitative trait loci (QTLs) analysis has been used to examine natural variation of phenotypes in the mouse somatosensory cortex, hippocampus, cerebellum, and amygdala. QTL analysis has also been utilized to map and identify genes underlying anatomical features such as muscle, organ, and body weights. However, this methodology has not been previously applied to identification of anatomical structures related to gustatory phenotypes. In this study, we used QTL analysis to map and characterize genes underlying tongue size, papillae number, and papillae area. In a set of 43 BXD recombinant inbred (RI) mice (n = 111) and 2 parental strains (C57BL/6J and DBA/2J; n = 7), we measured tongue length, width, and weight. In a subset of 23 BXD RI mice and the parental mice, we measured filiform and fungiform papillae number and fungiform papillae area. Using QTL linkage analysis (through WebQTL), we detected 2 significant and noninteracting QTLs influencing tongue length on chromosomes 5 and 7. We also found a significant QTL on chromosome 19 underlying fungiform papillae area and a suggestive QTL on chromosome 2 linked to fungiform papillae number. From these QTLs, we identified a number of candidate genes within the QTL intervals that include SRY-box containing gene, nebulin-related anchoring protein, and actin-binding LIM protein 1. This study is an important first step in identifying genetic factors underlying tongue size, papillae size, and papillae number using QTL analysis.     

Performance of ten inbred mouse strains following assisted reproductive technologies (ARTs)

Superovulation, in vitro fertilization, embryo cryopreservation, and embryo transfer are assisted reproductive technologies (ARTs) widely used in laboratory mice. Inbred strains of mice have inherent genetic differences that cause them to respond differently to these technologies. Knowing how common inbred strains will perform when used for ARTs will ensure the most efficient use of mice, time, and resources. In this study, we characterized the ability of 10 inbred strains: 129S1/SvImJ, A/J, BALB/cJ, BALB/cByJ, C3H/HeJ, C57BL/6J, DBA/2J, FVB/NJ, NOD/LtJ, and SJL/J to superovulate, fertilize in vitro, and produce live pups subsequent to embryo transfer. Three-week-old female mice were superovulated using eCG (5.0 IU) and hCG (5.0 IU). The resulting oocytes were fertilized in vitro in human tubal fluid medium with spermatozoa of the same strain. The following day, two-cell embryos were either transferred into pseudopregnant recipient females or cryopreserved. The cryopreserved embryos were later thawed and transferred into pseudopregnant recipient females. Differences in response to superovulation, fertilization, and number of live born produced after embryo transfer were observed between strains, substantiating the influence of genetic variability on ARTs. The response to the superovulation treatment varied among strains and ranged from 5+/-1(A/J) to 40+/-3 (129S1/SvImJ) normal oocytes per female. The average proportion of oocytes that fertilized ranged among strains from 24% (129S1/SvImJ) to 93% (DBA/2J and A/J). The average proportion of two-cell embryos that were transferred into recipient females and subsequently developed into live pups varied from 5% (A/J) to 53% (C57BL/6J) for fresh embryos and from 18% (BALB/cByJ) to 45% (129S1/SvImJ) for thawed embryos.     

Differences in vertebral structure and strength of inbred female mouse strains

This study assessed mouse strain-related differences in vertebral biomechanics and histomorphometry in inbred mice strains shown to differ in bone mineral content (BMC) and areal density (BMD) (as measured by pDEXA). Lumbar vertebrae L3 to L5 were collected from three mice strains (C3H/HeJ[C3], C57BL/6J[B6], and DBA/2J[D2], n=12/strain, 4-month-old female, 22.2 +/- 0.3g). BMC and BMD were measured in L3 and L4 using peripheral dual energy x-ray absorptiometry. The L4 vertebral body was then mechanically tested in compression to determine structural properties (ultimate/yield load, stiffness) from load-displacement curves and derive apparent material properties (ultimate/yield stress, and modulus of elasticity). L5 was processed for histomorphometric evaluation. Vertebral BMC and BMD were greater in C3 than in B6 and D2 mice. Vertebral trabecular/cancellous bone volume was smaller in C3 than in D2 and B6 mice. Trabecular bone formation rates were greater in D2 than in B6 and C3 mice. Osteoid surface was smaller in C3 mice than in B6 and D2 mice. Differences in osteoclast and mineralizing surfaces were not detected among the three mouse strains. In addition, there were no significant differences in biomechanical properties between the three strains. Despite the greatest BMC and areal BMD in C3 mice, the lack of strain-related differences in vertebral body strength data suggests that the biomechanical properties may be affected by the bone distribution and/or complex combination of cortical and cancellous bone at this site.     

Emotionality, exploratory behavior, and locomotion in aging inbred strains of mice.

Two inbred strains of mice, C57BL/6J and DBA/2J, ranging in age from 2 to 38 months, were tested in an open field using the free exploration method. Scores were obtained for locomotor activity, exploratory behavior and emotionality. Strain differences were observed for all three variables. Beginning at late maturity (12 months), locomotor activity decreased with increasing age. Exploratory behavior was at a low level for DBA/2J mice at all ages. For C57BL/6J mice, exploratory behavior decreased significantly between 2 and 6 months and remained stable thereafter. Emotionality remained unchanged with advancing age for both strains of mice.     

A locus on distal chromosome 11 (ahl8) and its interaction with Cdh23 ahl underlie the early onset, age-related hearing loss of DBA/2J mice

The DBA/2J inbred strain of mice is used extensively in hearing research, yet little is known about the genetic basis for its early onset, progressive hearing loss. To map underlying genetic factors we analyzed recombinant inbred strains and linkage backcrosses. Analysis of 213 mice from 31 BXD recombinant inbred strains detected linkage of auditory brain-stem response thresholds with a locus on distal chromosome 11, which we designate ahl8. Analysis of 225 N2 mice from a backcross of (C57BL/6JxDBA/2J) F1 hybrids to DBA/2J mice confirmed this linkage (LOD>50) and refined the ahl8 candidate gene interval. Analysis of 214 mice from a backcross of (B6.CAST-Cdh23 Ahl+ xDBA/2J) F1 hybrids to DBA/2J mice demonstrated a genetic interaction of Cdh23 with ahl8. We conclude that ahl8 is a major contributor to the hearing loss of DBA/2J mice and that its effects are dependent on the predisposing Cdh23 ahl genotype of this strain.     

Genetics of aryl hydrocarbon hydroxylase induction in mice: Additive inheritance in crosses between C3H/HeJ and DBA/2J

In certain strains of inbred mice, hepatic aryl hydrocarbon hydroxylase (AHH) activity is induced by parenteral injection of the carcinogen 3-methylchol-anthrene, whereas in other strains AHH activity is not induced. In most genetic crosses between inducible and noninducible strains, inducibility segregates as a single autosomal dominant gene. However, in crosses between strains C3H/HeJ (inducible) and DBA/2J (noninducible), inducibility segregates as a single gene and in an additive manner, with the inducibility of hybrid animals falling between that of the inducible parent and that of the noninducible parent. In crosses between strains C57BL/6J (inducible) and DBA/2J (the same noninducible parent crossed to C3H/HeJ), inducibility segregates as a dominant gene. This suggests that the genes responsible for inducibility of AHH in strains C3H/HeJ and C57BL/6J are not identical. Whether they represent different alleles at the same genetic locus or genes at different loci has not been determined.Formerly Postdoctoral Fellow of the Roche Institute of Molecular Biology.Recipient of Research Career Development Award 1 K4 AM CA 70, 186 from the National Institute of Arthritis and Metabolic Diseases. Formerly Chief, Mammalian Genetics Section, Roche Institute of Molecular Biology.     

Quantitative trait loci linked to thalamus and cortex gray matter volumes in BXD recombinant inbred mice

To investigate whether there are separate or shared genetic influences on the development of the thalamus and cerebral cortex, we identified quantitative trait loci (QTLs) for relevant structural volumes in BXD recombinant inbred (RI) strains of mice. In 34 BXD RI strains and two parental strains (C57BL/6J and DBA/2J), we measured the volumes of the entire thalamus and cortex gray matter using point counting and Cavalieri's rule. Heritability was calculated using analysis of variance (ANOVA), and QTL analysis was carried out using WebQTL (http://www.genenetwork.org). The heritability of thalamus volume was 36%, and three suggestive QTLs for thalamus volume were identified on chromosomes 10, 11 and 16. The heritability of cortical gray matter was 43%, and four suggestive QTLs for cortex gray matter volume were identified on chromosomes 2, 8, 16 and 19. The genetic correlation between thalamus and cortex gray matter volumes was 0.64. Also, a single QTL on chromosome 16 (D16Mit100) was identified for thalamus volume, cortex gray matter volume and Morris water maze search-time preference (r=0.71). These results suggest that there are separate and shared genetic influences on the development of the thalamus and cerebral cortex.     

Heterogeneity in the immune response to serotype b LPS of Actinobacillus actinomycetemcomitans in inbred strains of mice

We investigated the heterogeneity of the humoral immune responses to whole cells and lipopolysaccharide (LPS) of Actinobacillus actinomycetemcomitans serotype b and production of cytokines in inbred strains of mice. Nine such strains were tested: A/J (H-2(a)), C57BL/6 (H-2(b)), BALB/c (H-2(d)), DBA/2 (H-2(d)), B10.BR (H-2(k)), C3H/He (H-2(k)), C3H/HeJ (H-2(k)), DBA/1 (H-2(q)) and B10.S (H-2(s)). Mice were immunized intraperitoneally with whole cells of A. actinomycetemcomitans ATCC 43718 (serotype b) in phosphate buffered saline (PBS; pH 7.2) emulsified with an equal volume of Freund's incomplete adjuvant. Serum immunoglobulin G (IgG), immunoglobulin A (IgA) and immunoglobulin M (IgM) levels against A. actinomycetemcomitans were measured by an ELISA system. ELISA analysis, using LPS fractions from serotype a, b or c strains of A. actinomycetemcomitans as the coating antigens, revealed that mice strains C3H/He, C3H/HeJ, B10.BR and B10.S had an extremely high-IgM response against serotype b LPS. High-IgM titer sera contain also elevated levels of IgA antibodies to the antigen. To compare the cytokine production among inbred mice, the amounts of interleukin-4 (IL-4), interleukin-5 (IL-5), and interleukin-6 (IL-6) released from mouse splenocytes were measured using ELISA systems specific for these cytokines. A. actinomycetemcomitans serotype b LPS stimulation induced IL-6 release from murine splenocytes of all tested strains. However, IL-4 and IL-5 were detected only in high-IgM/IgA responders to A. actinomycetemcomitans serotype b LPS, not in low-IgM/IgA responders. Thus, we found a relationship between the humoral immune response to LPS of A. actinomycetemcomitans serotype b and production of type 2 cytokines by splenocytes.     

The susceptibility of inbred mice to infection with Brachylaima cribbi (Digenea: Brachylaimidae)

Susceptibility to infection with Brachylaima cribbi was studied in eight strains of inbred mice (AKR, C3H/HeJ, CBA/CaH, BALB/c, DBA/2J, SJL/J, A/J, C57BL/6J) and Swiss albino outbred mice by quantifying faecal egg excretion over the period of the infection. Preliminary experiments indicated that a combination of filtration/sedimentation/diethyl ether sedimentation was the most sensitive and reliable technique for quantification of eggs in faeces. Mice were infected with 13-15 wild-type B. cribbi metacercariae from naturally infected Cernuella virgata and in a second experiment with human-derived B. cribbi from laboratory-reared Helix aspersa. In both experiments C57BL/6J mice were the most susceptible having the highest egg excretion levels and the longest duration of infection. Worm burdens were assessed at 12 wpi for the wild-type and at 9 wpi for the human-derived infections, when the majority of mice were no longer excreting eggs. The numbers of worms recovered from the small intestine were few and there were no significant differences among the inbred or outbred groups of mice. We have found that C57BL/6J mice were the most susceptible to Brachylaima cribbi infection as assessed by excretion of eggs and provide a suitable model for a laboratory life-cycle.     

Differences among eight inbred strains of mice in motor ability and motor learning on a rotorod

The rotorod is commonly used to assess motor ability in mice. We examined a number of inbred strains to determine whether there is genetic variability in rotorod performance and motor learning. Mice received three trials per day for three days in a modified accelerating rotorod paradigm, and active rotation performance was calculated for each day. Male and female 129S1/SvImJ, A/J, BALB/cByJ, C3H/HeJ, C57BL/6J, CBA/J, DBA/2J and FVB/NJ mice were tested. Strain and sex differences were observed in motor performance. Motor learning also differed across strains, as some strains showed an improvement in performance over the three days while other strains did not. In certain strains the weight and body length of the mouse correlated with rotorod performance. The role of vision in motor performance on the rotorod was assessed by a comparison of C3H/HeJ mice (with retinal degeneration) and congenic C3A.BLiA- Pde6b ⁺ (Pdeb+) mice (without retinal degeneration). The sight-impaired C3H mice stayed on the rotorod longer than did their sighted Pdeb+ partners, although both strains improved across days. Thus, we have demonstrated a genetic component in rotorod performance, and we have shown that factors other than inherent motor ability can contribute to rotorod performance in mice.     

Variation in ten lysosomal hydrolase enzyme activities in inbred mouse strains

Activities of 10 lysosomal hydrolase enzymes (beta-hexosaminidase, beta-galactosidase, alpha-galactosidase, alpha-mannosidase, beta-mannosidase, alpha-L-fucosidase, beta-glucuronidase, alpha-glucosidase, alpha-N-acetylgalactosaminidase, and acid phosphatase) were determined in eight organs (brain, liver, kidney, spleen, heart, skeletal muscle, lung, and testis) in males and females of six inbred mouse strains (C57BL/6J, C3H/HeJ, DBA/2J, BALB/cJ, P/J, and 129/J). Examples of enzyme-specific variation, organ-specific variation, and enzyme- and organ-specific variation were found. New enzyme-specific variants with the features of systemic regulators for alpha-L-fucosidase and beta-mannosidase were found. Known variants were detected. Organ-specific variants had some of the properties expected for a new class of genes affecting multiple enzymes: organ-specific regulators.