Gene: 21Name: B3gnt1Family: Carbohydrate Metabolis...Subfamily: BrainiacAccession: AF092050GI: 9755418

Gene 21
Summary of Phenotypic Analysis

Changes related to genotype:

There were no other significant differences detected in the homozygous mutant animals when compared with age- and gender-matched wild-type control mice.

ES cells derived from the 129/OlaHsd mouse substrain were used to generate chimeric mice. F1 mice were generated by breeding with C57BL/6 females. F2 homozygous mutant mice were produced by intercrossing F1 heterozygous males and females.

Wild-type control mice and homozygous mutant mice were evaluated by the following examinations or tests:

When compared to age- and gender-matched wild-type control mice, homozygous mutants displayed a significant increase in the amount of time they spent exploring the central region during open field testing. This may indicate less fear or decreased anxiety. Also, tail suspension testing revealed a significant increase in the amount of time homozygous mutants remain immobile, compared to wild-type littermates. This may be associated with an increased depression-like state.

Gene 21
Behavior


Changes related to genotype:

Homozygous mutant and wild-type control mice were evaluated for phenotypic changes by testing on five behavioral tasks: Open field test, Tail suspension test, Rotarod test, Hot plate test, Startle/PPI, and Metrazol test.

Mouse ID numbers are as follows for the N1 generation:
9 homozygous mutant males (154677, 154680, 154689, 154693, 161184, 170125, 170127, 172566, 200732)
12 wild-type control males (154678, 154679, 154688, 154690, 154691, 161193, 161194, 161196, 170126, 172570, 172571, 200735)

ES cells derived from the 129/OlaHsd mouse substrain were used to generate chimeric mice.  F1 mice were generated by breeding with C57BL/6 females. The resultant F1N0 heterozygotes were backcrossed to C57BL/6 mice to generate F1N1 heterozygotes.  F2N1 homozygous mutant mice were produced by intercrossing F1N1 heterozygous males and females.

Behavior Findings:

When compared to age- and gender-matched wild-type control mice, homozygous mutants displayed a significant increase in the amount of time they spent exploring the central region during open field testing.  This may indicate less fear or decreased anxiety.  Also, tail suspension testing revealed a significant increase in the amount of time homozygous mutants remain immobile, compared to wild-type littermates.  This may be associated with an increased depression-like state. 

There were no other genotype-related differences noted between homozygous mutant and wild-type control mice for any other parameters evaluated during behavior testing.

 

Gene 21
Fertility

Both homozygous mutant males and females were fertile.  Their progeny were viable until weaning.

Three homozygous mutant mice of each gender were set up in a fertility mating one on one with each other at seven to thirteen weeks of age.  Two of the male and female pairs (178043 and 178047, 178045 and 178048) produced only two litters that were viable at weaning age. For the third pair (224993 and 240253), t he number of pups born from three litters was recorded.  Three weeks later, the live pups were counted and weaned.

Mouse ID numbers are as follows:

3 homozygous mutant males (178043, 178045, 224993)

3 homozygous mutant females (178047, 178048, 240253)

 

 

Gene 21
Expression Summary

RT-PCR Summary:
RNA transcripts are detectable in all tissues analyzed: brain, cortex, subcortical region, cerebellum, brainstem, olfactory bulb, eye, heart, lung, liver, pancreas, kidney, spleen, thymus, lymph nodes, bone marrow, skin, gallbladder, urinary bladder, pituitary gland, adrenal gland, salivary gland, skeletal muscle, tongue, stomach, small intestine, large intestine, cecum, testis, epididymis, seminal vesicle, coagulating gland, prostate gland, ovary and uterus.

LacZ Summary:
LacZ (beta-galactosidase) expression is detectable in brain and testis.

Expression:
Brain
In wholemount staining very faint X-Gal signals are detectable ventrally.

Male Reproductive Systems
Testis
Many spermatogenic cells of the seminiferous tubules show X-Gal staining.

No Expression:
LacZ (beta-galactosidase) expression is not detected in: spinal cord, sciatic nerve, eye, Harderian glands, thymus, spleen, lymph nodes, bone marrow, aorta, heart, lung, liver, gallbladder, pancreas, kidney, urinary bladder, larynx, trachea, esophagus, thyroid gland, parathyroid gland, pituitary gland, adrenal glands, salivary glands, tongue, skeletal muscle, skin, and female reproductive systems.

Comparing RT-PCR with lacZ data suggests that the lacZ reporter gene does not fully reflect the endogenous expression pattern.

Gene 21
Densitometry

There were no significant differences detected in the homozygous mutant animals when compared with age- and gender-matched wild-type control mice.

The following mice were evaluated by dual-energy x-ray absorptiometry.

49 Day Cohort Mouse ID numbers are as follows:
2 homozygous mutant females (135395, 135406)
3 homozygous mutant males (135399, 138902, 138903)
2 wild-type control females (135398, 135404)
2 wild-type control males (150179, 150181)

300 Day Cohort Mouse ID numbers are as follows:
2 homozygous mutant females (154658, 203889)
2 homozygous mutant males (215346, 225789)
2 wild-type control females (154660, 196619)
2 wild-type control males (196617, 201901)

Bone Mineral Density (BMD in g/cm
2 ), fat % (fat percentage expressed as a percentage of the soft tissue compartment), and R-value of soft tissue were calculated from Bone Mineral Content (BMC in g), bone and tissue areas (cm2 ), total tissue mass (g) generated by a PIXImus densitometer.

Densitometric Findings:

Certain changes were present in some mice that could occur spontaneously in mice of this age group. For example, two homozygous mutant female mice (154658, 203889) at 300 days had decreased body fat %. We have not reported these findings as phenotypic changes, but we have presented them here for your consideration. Other incidental densitometric differences may have been present between some mice. These findings are considered to represent background differences occasionally seen in this strain of mice, differences due to spontaneous disease, age-related changes, differences due to procedural artifacts, and/or differences of a nonspecific etiology. They are not considered to be genotype related.

 

Gene 21
Histopathology

There were no significant differences detected in the homozygous mutant animals when compared with age- and gender-matched wild-type control mice.

Tissues from the following mice were evaluated histologically.

49 Day Cohort Mouse ID numbers are as follows:
3 homozygous mutant females (135395, 135405, 135406)
3 homozygous mutant males (135399, 138902, 138903)
2 wild-type control females (135398, 135404)
2 wild-type control males (150179, 150181)

300 Day Cohort Mouse ID numbers are as follows:
2 homozygous mutant females (154658, 203889)
2 homozygous mutant males (215346, 225789)
2 wild-type control females (154660, 196619)
2 wild-type control males (196617, 201901)

No Significant Abnormalities:

Tissues examined and considered to have no genotypically-significant abnormality: brain, pituitary gland, ears, nasal cavity, salivary glands, oral cavity, lymph nodes, aorta, lungs, gallbladder, pancreas, spleen, kidneys, urinary bladder, stomach, small and large intestines, larynx, esophagus, trachea, thyroid gland, thymus gland, tongue, skeletal muscle, sciatic nerve, mammary glands, vertebrae, spinal cord, bone (skull, sternum, femur, tibia, and stifle joint), reproductive tract including gonads, eyes, Harderian glands, integumentary system (skin and either clitoral or preputial glands), and bone marrow.

Bone marrow was examined in sections of sternum, vertebrae, and/or femur and tibia. Marrow cellularity, myeloid:erythroid (M:E) ratio, myeloid and erythroid maturation sequences, and numbers of megakaryocytes were evaluated.

Certain histopathological lesions, including: mild bone marrow hypocellularity in two homozygous mutant females (135405, 135406) at 49 days; and, mild multifocal necrosis with mineralization in brown adipose tissue, moderate focal necrosis with mineralization in fat associated with the pancreas, and mild thymic atrophy in one homozygous mutant female (135405), were present that occasionally occur spontaneously in mice of this age group. Also, two homozygous mutant males (215346, 225789) had minimal to mild retinal dysplasia at 300 days.  We are not reporting these findings as a phenotypic change, but we present them here for your consideration.

Incidental lesions may have been present in some tissues. These findings are considered to represent background lesions occasionally seen in this strain of mice, lesions due to spontaneous disease, age-related lesions, lesions due to procedural artifacts and/or lesions of a nonspecific etiology. They are not considered to be genotype related.

Gene 21
Necropsy

There were no significant differences detected in the homozygous mutant animals when compared with age- and gender-matched wild-type control mice.

The following mice were necropsied. Body weight, body length, and organ weights were obtained and gross pathological findings were recorded.

49 Day Cohort Mouse ID numbers are as follows:
3 homozygous mutant females (135395, 135405, 135406)
3 homozygous mutant males (135399, 138902, 138903)
2 wild-type control females (135398, 135404)
2 wild-type control males (150179, 150181)

300 Day Cohort Mouse ID numbers are as follows:
2 homozygous mutant females (154658, 203889)
2 homozygous mutant males (215346, 225789)
2 wild-type control females (154660, 196619)
2 wild-type control males (196617, 201901)

Mice were examined for the following observables: adrenal glands, body length, body weight, bone marrow, bone-cranium, bone-femur, bone-sternum, bone-stifle joint, bone-vertebral column, brain, cecum, colon, duodenum, epididymis-seminal vesicle, esophagus, eyes, gallbladder, general appearance, Harderian glands, heart, heart weight, ileum, jejunum, kidneys, kidney weight, liver, liver weight, lungs, lymph nodes, mesentery, ovaries, pancreas, penis, salivary glands, sciatic nerve, scrotum, skeletal muscle, skin, skinned mouse, spleen, spleen weight, stomach, testes, testes-epididymis weight, thymus, thymus weight, tongue, trachea, urinary bladder, urine, uterus and vagina (gender specific observables apply to appropriate gender).

Necropsy Findings:

There were no genotype-related or biologically significant differences noted between mutant and wild-type control mice for any of the parameters evaluated at necropsy. Incidental lesions may have been present in some tissues. These findings were considered to represent background lesions occasionally seen in this strain of mice, lesions due to spontaneous disease, age-related lesions, lesions due to procedural artifacts, and/or lesions of a nonspecific etiology. They were not considered to be genotype related.

Body and Organ Weight Findings:

One homozygous mutant female (135405) at 49 days had low body weight, reduced body length and low organ weights compared to concurrent control mice and historical reference ranges. This mouse was noted to be dwarfed at physical examination. One homozygous mutant male (225789) at 300 days had increased spleen weight and spleen weight to body weight ratio and this finding was histologically correlated with mild increased extramedullary hematopoiesis in the spleen. We are not reporting these findings as phenotypic changes, but we present them here for your consideration.

Other differences in body length, body weight, organ weights, and/or organ weight to body weight ratios were present between individual mice. The variability between mice usually fell within our historical reference ranges and was not correlated with genotype.

Gene 21
Clinical Chemistry


There were no significant differences detected in the homozygous mutant animals when compared with age- and gender-matched wild-type control mice.

Serum samples from the following mice were evaluated by a clinical biochemistry panel. The data are compiled from the N1F2 and N2F2 generations.

49 Day Cohort Mouse ID numbers are as follows:
3 homozygous mutant females (135406, 142328, 179481)
3 homozygous mutant males (135399, 138902, 138903)
2 wild-type control females (135404, 142330)
2 wild-type control males (150179, 150181)

90 Day Cohort Mouse ID numbers are as follows:
4 homozygous mutant females (154658, 154669, 154696, 161190)
3 homozygous mutant males (215346, 225789, 327768)
4 wild-type control females (154660, 154666, 154668, 161189)
4 wild-type control males (196617, 201901, 214503, 215343)

180 Day Cohort Mouse ID numbers are as follows:
4 homozygous mutant females (154658, 154669, 154696, 161190)
2 homozygous mutant males (215346, 225789)
4 wild-type control females (154660, 154666, 154668, 161189)
4 wild-type control males (196617, 201901, 214503, 215343)

300 Day Cohort Mouse ID numbers are as follows:
2 homozygous mutant females (154658, 203889)
2 homozygous mutant males (215346, 225789)
2 wild-type control females (154660, 196619)
2 wild-type control males (196617, 201901)

When compared to age- and gender-matched wild-type control mice, two 300-day homozygous mutant females (154658, 203889) and one 300-day homozygous mutant male (215346) had an increased level of Blood Urea Nitrogen. Also one 300-day homozygous mutant male (215346) had low level of Cholesterol, High Density Lipoprotein and Triglycerides .We are not reporting these findings as phenotypic changes, but we present them here for your consideration.

Values for the various analytes evaluated were generally similar between homozygous mutant and wild-type control mice. Variations in clinical chemistry values, if present, were not consistent with genotype and thus were not considered phenotypically relevant.

Gene 21
Hematology


There were no significant differences detected in the homozygous mutant animals when compared with age- and gender-matched wild-type control mice.

Blood samples from the following mice were evaluated by a complete blood count and differential cell count. The data are compiled from the N1F2 and N2F2 generations.

49 Day Cohort Mouse ID numbers are as follows:
3 homozygous mutant females (135405, 138899, 179483)
3 homozygous mutant males (135399, 138902, 138903)
2 wild-type control females (135398, 135404)
2 wild-type control males (150179, 150181)

90 Day Cohort Mouse ID numbers are as follows:
4 homozygous mutant females (154658, 154669, 154696, 161190)
3 homozygous mutant males (215346, 225789, 327768)
4 wild-type control females (154660, 154666, 154668, 161189)
4 wild-type control males (196617, 201901, 210997, 214503)

180 Day Cohort Mouse ID numbers are as follows:
4 homozygous mutant females (154658, 154669, 154696, 161190)
2 homozygous mutant males (215346, 225789)
4 wild-type control females (154660, 154666, 154668, 161189)
4 wild-type control males (196617, 201901, 214503, 215343)

300 Day Cohort Mouse ID numbers are as follows:
2 homozygous mutant females (154658, 203889)
1 homozygous mutant male (215346)
2 wild-type control females (154660, 196619)
2 wild-type control males (196617, 201901)

Although minor variations of hematological values were present in some animals, these changes were not consistent with genotype and thus were not considered phenotypically relevant.

Gene 21
Physical Examination

There were no significant differences detected in the homozygous mutant animals when compared with age- and gender-matched wild-type control mice.

The following mice were evaluated by physical examination.

49 Day Cohort Mouse ID numbers are as follows:
3 homozygous mutant females (135395, 135405, 135406)
3 homozygous mutant males (135399, 138902, 138903)
2 wild-type control females (135398, 135404)
2 wild-type control males (150179, 150181)

300 Day Cohort Mouse ID numbers are as follows:
2 homozygous mutant females (154658, 203889)
2 homozygous mutant males (215346, 225789)
2 wild-type control females (154660, 196619)
2 wild-type control males (196617, 201901)

Mice were examined for the following observables: anus, behavior, body shape, claws, coat - fur, coat color - back, coat color - belly, ear - left, ear - right, eye - left, eye - right, eye color - left, eye color - right, feces, feces color, feces exam, forelimb - left, forelimb - right, forelimb number of amputated digits - left, forelimb number of amputated digits - right, forelimb number of digits - left, forelimb number of digits - right, general appearance, genitals - female, genitals - male, hair type, head shape, hindlimb - left, hindlimb - right, hindlimb number of amputated digits - left, hindlimb number of amputated digits - right, hindlimb number of digits - left, hindlimb number of digits - right, injuries, lesions, limb shape, locomotor, lumps - masses, mammary glands exam, mice in cage, respiration, skin appearance, snout, swelling - joints, tail, teeth color, teeth length, urine, urine color, urine exam and whiskers (gender specific observables apply to appropriate gender).

When compared to age- and gender-matched wild-type control mice one homozygous female (135405) was weak, dehydrated, and dwarfed, with a hunched body and abnormal, overgrown teeth. We are not reporting these findings as phenotypic changes, but we present them here for your consideration.

There were no other genotype-related or biologically significant differences noted between mutant and wild-type control mice for any of the parameters evaluated at physical examination.

Gene 21
Aging Metrics

There were no significant differences detected in the homozygous mutant mice when compared with age- and gender-matched wild-type control mice.

Body weights and body lengths were measured for mice at 49, 90, 180, and 300 days of age.

49 Day Cohort Mouse ID numbers are as follows:
4 homozygous mutant females (154658, 154669, 154696, 161190)
5 homozygous mutant males (214501, 214504, 215346, 225789, 310366)
3 wild-type control females (154660, 154668, 161189)
4 wild-type control males (196617, 201901, 210997, 214503)

90 Day Cohort Mouse ID numbers are as follows:
4 homozygous mutant females (154658, 154669, 154696, 161190)
3 homozygous mutant males (215346, 225789, 327768)
3 wild-type control females (154660, 154668, 161189)
4 wild-type control males (196617, 201901, 210997, 214503)

180 Day Cohort Mouse ID numbers are as follows:
4 homozygous mutant females (154658, 154669, 154696, 161190)
4 wild-type control females (154660, 154666, 154668, 161189)
3 wild-type control males (196617, 201901, 214503)

300 Day Cohort Mouse ID numbers are as follows:
2 homozygous mutant females (154696, 179477)
2 wild-type control females (201906, 201908)
2 wild-type control males (214503, 215343)

Differences in body length and body weight were present between individual mice. The variability between mice usually fell within our historical reference ranges and was not correlated with genotype.