Gene: 1042Name: Gabbr1Family: GPCRSubfamily: Metabolic gaba recepto...Accession: AF114168GI: 4544336

Gene 1042
Summary of Phenotypic Analysis

Changes related to genotype:

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

Weaned progeny from the heterozygous matings were genotyped. The homozygous mutant mice that were clinically ill were necropsied at 20-25 days. The genotype ratio suggests a juvenile lethal phenotype.

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.

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

When compared to age- and gender-matched wild-type control mice, two homozygous mutant male mice and one homozygous mutant female mouse had abnormal behavior (crouching). Two homozygous mutant female mice and one homozygous mutant male mouse from the 20-25 day cohort had a hunched posture. One homozygous mutant male mouse and three homozygous mutant female mice were hypoactive and weak. One homozygous mutant male mouse and two homozygous mutant female mice were dehydrated. When compared to age- and gender-matched wild-type control mice, four homozygous mutant mice had decreased subcutaneous fat observed at necropsy examination.

Gene 1042
Behavior


Changes related to genotype:

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

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

Mouse ID numbers are as follows:

11 heterozygous mutant males (175674, 164364, 164350, 180906, 164363, 164352, 164348, 180904, 180909, 168173, 180902)
11 wild-type control males (164349, 164353, 180905, 180907, 168174, 164351, 164366, 175653, 180901, 164365, 180908)


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 heterozygous mutant mice were produced by intercrossing F1N1 heterozygous males and females.

Behavior Findings:
There were no genotype-related or biologically significant differences noted between heterozygous mutant and wild-type control mice for any of the parameters evaluated during behavior testing.

Gene 1042
Fertility

Fertility on homozygous animals could not be determined, because of developmental lethality. However, both heterozygous males and females were fertile. Their progeny were viable until weaning, which suggests no abnormalities in the ability of the mutant females to nurture their pups.

Gene 1042
Expression Summary

RT-PCR Summary:
RNA transcripts are detectable in: brain, cortex, subcortical region, cerebellum, brainstem, olfactory bulb, spinal cord, eye, heart, lung, 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, uterus and white fat.

No RNA transcripts are detectable in Harderian gland, liver and pancreas.

LacZ Summary:
LacZ (beta-galactosidase) expression is detectable in brain, spinal cord, eyes, Harderian glands, spleen, lymph nodes, bone marrow, aorta, heart, lung, gallbladder, pancreas, kidney, urinary bladder, trachea, larynx, esophagus, thyroid gland, pituitary gland, adrenal glands, salivary glands, tongue, skin, male and female reproductive systems.  In many tissues, lacZ expression is detectable in endothelial and smooth muscle cells of blood vessels.

Expression:
Brain
In wholemount staining very strong X-Gal staining is detectable throughout the whole brain including olfactory bulb, cerebrum, cerebellum and brainstem.  On coronal sections very strong lacZ expression is detectable in practically all nuclei of sections from forebrain, midbrain, cerebellum and brainstem. Further lacZ expression is detectable in meninges and blood vessels.

Spinal cord
Very strong lacZ expression is detectable scattered throughout both gray and white matter.  Strongest expression is detectable in the dorsal horns and central canal.

Eyes
Strong lacZ expression is detectable in the ganglion cell, inner nuclear, outer nuclear and pigment layers of the retina.  Further expression is detectable in lens and sclera.

Harderian Glands
LacZ expression is detectable in blood vessels.

Thymus
Weak lacZ expression is detectable in a few cells.

Spleen
LacZ expression is detectable in distinct cells.

Lymph Nodes
Weak to moderate lacZ expression is detectable in distinct cells.

Bone Marrow Smear
Weak to moderate lacZ expression is detectable in very few cells.

Aorta
LacZ expression is detectable in tunica media and periaortic fat.

Heart
Weak lacZ expression is detectable in valves, aortic root, and blood vessels.  Very weak expression is detectable in a few cells in the myocardium. Strong lacZ expression is detectable in ganglia

Lung
LacZ expression is detectable in epithelial cells and smooth muscle of bronchioles. In blood vessels endothelial cells and smooth muscle cells express lacZ.

Gallbladder
Very weak lacZ expression is detectable in the smooth muscle cells of the wall.

Pancreas
LacZ expression is detectable in blood vessels.

Kidney
LacZ expression is detectable in tubules, glomeruli and endothelial cells.  Weak expression is detectable in papilla, pelvis and blood vessels.

Urinary Bladder
Moderate to strong lacZ expression is detectable in some mucosal cells.  Faint lacZ expression is detectable in smooth muscle cells of the muscularis.

Trachea
LacZ expression is detectable in chondrocytes and in a few cells of the mucosal epithelium.

Larynx
LacZ expression is detectable in chondrocytes, mucosal epithelium, submucosal glands, mucous glands and muscle layer. Strong lacZ expression is detectable in ganglia. 

Esophagus
Strong lacZ expression is detectable in ganglia.

Thyroid Gland
LacZ expression is detectable in endothelial and smooth muscle cells of blood vessels.

Pituitary Gland
Strong lacZ expression is detectable in pars distalis, pars intermedia and pars nervosa.

Adrenal Glands
Strong lacZ expression is detectable in medulla and capsule.

Salivary Glands
Strong lacZ expression is detectable in ganglia and endothelial cells of blood vessels.  Moderate lacZ expression is detectable in some acini.

Tongue
LacZ expression is detectable in mucous glands, minor salivary glands, blood vessels and ganglia. Strongest staining is observed in ganglia.

Skin
LacZ expression is detectable in epidermis, hair follicles and blood vessels.

Skin of the Ear
LacZ expression is detectable in epidermis, hair follicles and chondrocytes.

Male Reproductive Systems
Testis
Weak lacZ expression is detectable in a few cells of the interstitium. Further lacZ expression is detectable in blood vessels.

Penis
Strong lacZ expression is detectable in dermis.  Moderate lacZ expression is detectable throughout the body, chondrocytes of the os and in blood vessels.

Seminal Vesicles
Strong lacZ expression is detectable in smooth muscle cells of the capsule.

Coagulating Gland
Strong lacZ expression is detectable in smooth muscle cells of the capsule.

Prostate and Ampullary Gland
LacZ expression is detectable in smooth muscle cells of the capsule and in ganglia.

Female Reproductive Systems
Oviduct/Uterus
LacZ expression is detectable in epithelial and smooth muscle cells of Fallopian tubules.  In uterus weak lacZ expression is detectable in the myometrium.  Further lacZ expression is detectable in blood vessels.

Vagina
Weak lacZ expression is detectable in smooth muscle cells in the muscularis and in blood vessels. Strong lacZ expression is detectable in ganglia. 


No Expression: 
LacZ expression is not detected in sciatic nerve, liver and skeletal muscle.

Gene 1042
Densitometry

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

The following mice were evaluated by dual-energy x-ray absorptiometry. The data are compiled from the N0F2 and N1F2 generations.

49 Day Cohort Mouse ID numbers are as follows:
1 homozygous mutant male (151360)
3 heterozygous mutant females (175680, 175685, 180915)
3 heterozygous mutant males (180910, 180911, 180912)
2 wild-type control females (151361, 151377)
2 wild-type control males (151374, 193745)

300 Day Cohort Mouse ID numbers are as follows:
2 heterozygous mutant females (164356, 164357)
2 heterozygous mutant males (187045, 187046)
2 wild-type control females (164367, 164368)
2 wild-type control males (187042, 187044)

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

Densitometric Findings: 
 
Incidental densitometric differences were present between some mice. These findings were considered to represent background differences occasionally seen in this strain of mice, differences due to spontaneous disease, age-related differences, and/or differences of a nonspecific etiology. They were not considered to be genotype related.

Gene 1042
Histopathology

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

Tissues from the following mice were evaluated histologically. The data are compiled from the N0F2 and N1F2 generations.

20 Day Cohort Mouse ID numbers are as follows:
5 homozygous mutant females (160016, 168185, 168186, 168293, 168305)
2 homozygous mutant males (168178, 207900)
1 heterozygous mutant female (168183)
1 heterozygous mutant male (168176)
1 wild-type control female (168184)
1 wild-type control male (168177)

49 Day Cohort Mouse ID numbers are as follows:
1 homozygous mutant male (151360)
3 heterozygous mutant females (175680, 175685, 180915)
3 heterozygous mutant males (180910, 180911, 180912)
2 wild-type control females (151361, 151377)
2 wild-type control males (151374, 193745)

300 Day Cohort Mouse ID numbers are as follows:
2 heterozygous mutant females (164356, 164357)
2 heterozygous mutant males (187045, 187046)
2 wild-type control females (164367, 164368)
2 wild-type control males (187042, 187044)

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.

Two homozygous mutant female mice (160016, 168186) have mild to moderate thymus atrophy. We are not reporting these findings as phenotypic changes, but we present them here for your consideration.

Other 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 1042
Necropsy 

Changes related to genotype:

There were no significant differences detected in the heterozygous mutant mice 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. The data are compiled from the N0F2 and N1F2 generations.

20 Day Cohort Mouse ID numbers are as follows:
5 homozygous mutant females (160016, 168185, 168186, 168293, 168305)
2 homozygous mutant males (168178, 207900)
1 heterozygous mutant female (168183)
1 heterozygous mutant male (168176)
1 wild-type control female (168184)
1 wild-type control male (168177)

49 Day Cohort Mouse ID numbers are as follows:
1 homozygous mutant male (151360)
3 heterozygous mutant females (175680, 175685, 180915)
3 heterozygous mutant males (180910, 180911, 180912)
2 wild-type control females (151361, 151377)
2 wild-type control males (151374, 193745)

300 Day Cohort Mouse ID numbers are as follows:
2 heterozygous mutant females (164356, 164357)
2 heterozygous mutant males (187045, 187046)
2 wild-type control females (164367, 164368)
2 wild-type control males (187042, 187044)

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, feces, gallbladder, general appearance, Harderian glands, heart, heart weight, ileum, jejunum, kidney weight, kidneys, 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:
When compared to age- and gender-matched wild-type control mice, in the 20 day cohort four homozygous mutant mice, three females (160016, 168186, 168305) and one male (168178), had decreased subcutaneous fat. There were no other genotype-related or biologically significant differences noted between mutant and wild-type control mice.

Incidental lesions may have been present in some tissues. For example, a 300 day heterozygous mutant male (187045) was reported to have a peripancreatic nodule (see image) that had a histopathological correlate of fat necrosis. 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:
In the 20 day cohort, two homozygous mutant female mice (168186, 168305) had lower body weight compared to wild-type control mice. Additionally, three 20 day cohort homozygous mutant female mice (160016, 168186, 168305) had lower thymus weights. This finding corelates with the histopathological finding of thymus hypoplasia for some of these mice (160016, 168186). 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 1042
Clinical Chemistry

There were no significant differences detected in the homozygous or heterozygous mutant mice 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 N0F2 and N1F2 generations.

20 Day Cohort Mouse ID numbers are as follows:
1 homozygous mutant female (168185)
1 heterozygous mutant male (168176)
1 wild-type control female (168184)
2 wild-type control males (168177, 193739)

49 Day Cohort Mouse ID numbers are as follows:
1 homozygous mutant male (151360)
3 heterozygous mutant females (175394, 180915, 217440)
3 heterozygous mutant males (180910, 180911, 180912)
2 wild-type control females (151361, 151377)
2 wild-type control males (151374, 184345)

90 Day Cohort Mouse ID numbers are as follows:
4 heterozygous mutant females (164370, 168179, 182143, 182144)
4 heterozygous mutant males (187045, 187046, 193743, 198462)
4 wild-type control females (164367, 184354, 187047, 187048)
3 wild-type control males (187042, 187044, 193747)

180 Day Cohort Mouse ID numbers are as follows:
3 heterozygous mutant females (164356, 164357, 164370)
3 heterozygous mutant males (187045, 193743, 193746)
3 wild-type control females (164367, 164368, 164371)
3 wild-type control males (187042, 187044, 193744)

300 Day Cohort Mouse ID numbers are as follows:
2 heterozygous mutant females (164356, 164357)
2 heterozygous mutant males (187045, 187046)
2 wild-type control females (164368, 168181)
2 wild-type control males (187042, 187044)

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

Gene 1042
Hematology

There were no significant differences detected in the homozygous or heterozygous mutant mice 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 N0F2 and N1F2 generations.

20 Day Cohort Mouse ID numbers are as follows:
2 homozygous mutant females (168293, 168305)
1 homozygous mutant male (207900)
1 wild-type control female (168184)
1 wild-type control male (168177)

49 Day Cohort Mouse ID numbers are as follows:
1 homozygous mutant male (151360)
3 heterozygous mutant females (175680, 175685, 180915)
3 heterozygous mutant males (180910, 180911, 180912)
2 wild-type control females (151361, 151377)
1 wild-type control male (151374)

90 Day Cohort Mouse ID numbers are as follows:
4 heterozygous mutant females (164356, 164357, 164370, 168179)
4 heterozygous mutant males (187045, 187046, 193743, 193746)
4 wild-type control females (164367, 164368, 164371, 164372)
4 wild-type control males (187042, 187044, 193744, 193747)

180 Day Cohort Mouse ID numbers are as follows:
4 heterozygous mutant females (164356, 164357, 164370, 168179)
4 heterozygous mutant males (187045, 187046, 193743, 193746)
4 wild-type control females (164367, 164368, 164371, 164372)
4 wild-type control males (187042, 187044, 193744, 193747)

300 Day Cohort Mouse ID numbers are as follows:
2 heterozygous mutant females (164356, 164357)
2 heterozygous mutant males (187045, 187046)
2 wild-type control females (164368, 168180)
2 wild-type control males (187042, 198464)

The neutrophil percentage for one 20 day cohort homozygous mutant female (168205) was greater than the wild-type control female, but there is not enough data to form a historical (whole population) reference interval for comparison. This change is not being presented as a phenotypic change but is presented for your consideration. Although minor variations of other hematological values were present in some mice, these changes were not consistent with genotype and, thus, were not considered phenotypically relevant.

Gene 1042
Physical Examination

Changes related to genotype:

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

The following mice were evaluated by physical examination. The data are compiled from the N0F2 and N1F2 generations.

20 Day Cohort Mouse ID numbers are as follows:
5 homozygous mutant females (160016, 168185, 168186, 168293, 168305)
2 homozygous mutant males (168178, 207900)
1 heterozygous mutant female (168183)
1 heterozygous mutant male (168176)
1 wild-type control female (168184)
1 wild-type control male (168177)

49 Day Cohort Mouse ID numbers are as follows:
1 homozygous mutant male (151360)
3 heterozygous mutant females (175680, 175685, 180915)
3 heterozygous mutant males (180910, 180911, 180912)
2 wild-type control females (151361, 151377)
2 wild-type control males (151374, 193745)

300 Day Cohort Mouse ID numbers are as follows:
2 heterozygous mutant females (164356, 164357)
2 heterozygous mutant males (187045, 187046)
2 wild-type control females (164367, 164368)
2 wild-type control males (187042, 187044)

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, 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, mice in cage, respiration, skin appearance, snout, swelling - joints, tail, teeth color, teeth length, urine, and whiskers. (Gender-specific observables apply to appropriate gender.)

When compared to age- and gender-matched wild-type control mice, one homozygous mutant female mouse (168186) from the 20 day cohort, one homozygous mutant male mouse (168178) from the 20 day cohort, and one homozygous mutant male mouse (151360) from the 49 day cohort had abnormal behavior. In the 20 day cohort, three homozygous mutant female mice (160016, 168186, 168305) and one homozygous mutant male mouse (168178) had hunched posture and were hypoactive and weak (see image). Also in the 20 day cohort, two homozygous mutant female mice (168186, 168305) and one homozygous mutant male mouse (168178) were dehydrated.

Individual homozygous mutant mice had only occasional other minor differences in observed physical features compared to wild-type control mice. These findings are considered to represent individual variability, background features occasionally seen in this strain of mice, findings due to spontaneous disease, age-related findings, procedural artifacts, and/or findings of a nonspecific etiology. However, none of these differences was regarded as biologically significant or genotype related.

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 1042
Aging Metrics

There were no significant differences detected in the heterozygous 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 heterozygous mutant females (164356, 164357, 164370, 168179)
4 heterozygous mutant males (187045, 187046, 193743, 193746)
4 wild-type control females (164367, 164368, 164371, 164372)
4 wild-type control males (187042, 187044, 193744, 193747)

90 Day Cohort Mouse ID numbers are as follows:
4 heterozygous mutant females (164356, 164357, 164370, 168179)
3 heterozygous mutant males (187045, 187046, 193743)
4 wild-type control females (164367, 164368, 164371, 164372)
3 wild-type control males (187042, 187044, 193744)

180 Day Cohort Mouse ID numbers are as follows:
4 heterozygous mutant females (164356, 164357, 164370, 168179)
4 heterozygous mutant males (187045, 187046, 193743, 193746)
4 wild-type control females (164367, 164368, 164371, 164372)
4 wild-type control males (187042, 187044, 193744, 193747)

300 Day Cohort Mouse ID numbers are as follows:
2 heterozygous mutant females (164370, 168179)
2 heterozygous mutant males (193743, 193746)
2 wild-type control females (164371, 164372)
2 wild-type control males (193744, 193747)

Body Weight and Length Findings:

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.