Gene: 1623Name: Gria3Family: ChannelSubfamily: Glutamate GatedAccession: NM_016886GI: 8393312

Gene 1623
Summary of Phenotypic Analysis


Changes related to genotype:

There were no other significant differences detected in the female homozygous and male hemizygous mutant mice when compared with age- and gender-matched heterozygous and 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. The resultant F1N0 heterozygotes were backcrossed to C57BL/6 mice to generate F1N1 heterozygotes.  F2N1 mutant mice were produced by intercrossing F1N1 heterozygous males and females.

As this gene was X-linked, the cohort consists of homozygous mutant females, hemizygous mutant males (-/0), heterozygous control females, and wild-type control males (+/0). No wild-type control females or heterozygous control males were analyzed for this target, as such mice cannot be generated from a male -/0 x female -/+ mating.

Female homozygous mutant mice, male hemizygous mutant mice, female heterozygous control mice, and male wild-type control mice were evaluated by the following examinations or tests:

When compared to age- and gender-matched wild-type control mice, body weight and/or body weight/body length ratio were low in two 300 day homozygous mutant females at necropsy examination. When compared to age- and gender-matched wild-type control mice, total tissue mass was low at densitometer examination in 300 day homozygous mutant females. When compared to age- and gender-matched wild-type control mice, body weight and body weight/body length ratio were low at aging metrics examination in one day hemizygous mutant male at 49, 90 and 300 days, and in the two 300 day homozygous mutant females. 

Gene 1623
Behavior

Hemizygous 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, Startle test, Tail flick test, Hot plate test, and Metrazol test.

Mouse ID numbers are as follows for the N1 generation:
11 hemizygous mutant males (239067, 241938, 247383, 247384, 247391, 247393, 247397, 247418, 258105, 258107, 258108)
12 wild-type control males (239062, 239068, 241934, 241935, 247381, 247385, 247386, 247392, 247419, 247420, 258103, 258104)

ES cells derived from 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 hemizygous mutant mice were produced by intercrossing F1N1 heterozygous males and females.

Behavior Findings:
When compared to age- and gender-matched wild-type control mice, hemizygous mutant mice exhibited a significantly increased latency to lick a hindpaw or jump during hot plate testing, indicating a possible increased pain threshold phenotype.  However, their response latency was less than the historical mean for this assay.

When compared to age- and gender-matched wild-type control mice, hemizygous mutant mice required a significantly higher dose of metrazol to reach the "1st twitch" stage of the seizure response during metrazol testing, indicating a possible lower propensity towards seizure phenotype.

When compared to age- and gender-matched wild-type control mice, hemizygous mutant mice displayed a significantly decreased startle response to 110 and 120 db sound stimuli.

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

Gene 1623
Fertility

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

Three hemizygous mutant male and three homozygous female mice were set up in a fertility mating one on one with each other at seven to ten weeks of age.  One mating pair (244790, 244784) produced no viable progeny at weaning.   The 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 hemizygous mutant males (236392, 247394, 244790)

3 homozygous mutant females (236400, 247380, 244784)

 

 

Gene 1623
Expression Summary

RT-PCR Summary:
Low levels of RNA transcripts are detectable in brain, cortex, subcortical region, cerebellum, brainstem, olfactory bulb, adrenal gland and salivary gland.

No RNA transcripts are detectable in spinal cord, eye, Harderian glands, heart, lung, liver, pancreas, kidney, spleen, thymus, lymph nodes, bone marrow, skin, gallbladder, urinary bladder, pituitary gland, skeletal muscle, tongue, stomach, small intestine, large intestine, cecum, testis, epididymis, seminal vesicle, coagulating gland, prostate gland, ovaries, uterus and white fat.

LacZ Summary:
LacZ expression was detected in most tissues and organs examined.  Staining was observed in smooth muscle cells, neurons, endothelium, chondrocytes and other cell types.

LacZ expression was detected in:  brain, sciatic nerve, eyes, thymus, spleen, lymph nodes, aorta, heart, lung, liver, pancreas, kidney, urinary bladder, larynx, thyroid gland, parathyroid gland, pituitary gland, adrenal glands, skin, testis, ovary and uterus.

LacZ expression was not detected in:  spinal cord, bone marrow and skeletal muscle.

Gene 1623
Densitometry

Changes related to genotype:

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

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

49 Day Cohort Mouse ID numbers are as follows:
3 homozygous mutant females (236396, 236398, 236399)
2 heterozygous mutant females (236395, 236397)
3 hemizygous mutant males (236401, 236405, 236409)
2 wild-type control males (236389, 236390)

300 Day Cohort Mouse ID numbers are as follows:
2 homozygous mutant females (236416, 239049)
2 heterozygous mutant females (241939, 241941)
2 hemizygous mutant males (236410, 236411)
2 wild-type control males (236406, 239079)

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:

When compared to age- and gender-matched wild-type control mice, total tissue mass was low in 300 day homozygous mutant females. These findings correlated with low body weight and/or body weight/body length ratio at necropsy and aging metrics examinations.

Other incidental densitometric differences may have been 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 changes, differences due to procedural artifacts, and/or differences of a nonspecific etiology. They were not considered to be genotype related.

Gene 1623
Histopathology

There were no significant differences detected in the female homozygous and male hemizygous mutant mice when compared with age- and gender-matched heterozygous and 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 (236396, 236398, 236399)
2 heterozygous mutant females (236395, 236397)
3 hemizygous mutant males (236401, 236405, 236409)
2 wild-type control males (236389, 236390)

300 Day Cohort Mouse ID numbers are as follows:
1 homozygous mutant female (236416)
1 heterozygous mutant female (241939)
1 hemizygous mutant male (236410)

No Significant Abnormalities:

The following tissues were examined and considered to have no genotype-related abnormality: brain, pituitary gland, ears, nasal cavity, salivary glands, oral cavity, lymph nodes, aorta, lungs, liver, 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.

Incidental lesions were 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, and/or lesions of a nonspecific etiology. They were not considered to be genotype related.

Gene 1623
Necropsy 

Changes related to genotype:

There were no other significant differences detected in the female homozygous and male hemizygous mutant mice when compared with age- and gender-matched heterozygous and 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 (236396, 236398, 236399)
2 heterozygous mutant females (236395, 236397)
3 hemizygous mutant males (236401, 236405, 236409)
2 wild-type control males (236389, 236390)

300 Day Cohort Mouse ID numbers are as follows:
2 homozygous mutant females (236416, 239049)
2 heterozygous mutant females (241939, 241941)
2 hemizygous mutant males (236410, 236411)

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, 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 the 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, and/or lesions of a nonspecific etiology. They were not considered to be related to genotype.

Body and Organ Weight Findings:

When compared to age- and gender-matched wild-type control mice, body weight and/or body weight/body length ratio were low in two 300 day homozygous mutant females. These findings correlated with low body weight at aging metrics and were thought to be related to genotype.

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 1623
Clinical Chemistry

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

Serum samples from the following mice were evaluated by a clinical chemistry panel.

49 Day Cohort Mouse ID numbers are as follows:
3 homozygous mutant females (236398, 236399, 244787)
3 hemizygous mutant males (236401, 236405, 236409)
2 heterozygous mutant females (236395, 236397)
2 wild-type control males (236389, 236390)

90 Day Cohort Mouse ID numbers are as follows:
4 homozygous mutant females (236416, 239049, 239054, 239056)
3 hemizygous mutant males (236410, 239082, 258084)
4 heterozygous mutant females (241939, 241942, 261199, 261202)
5 wild-type control males (236406, 236407, 236412, 239079, 239081)

180 Day Cohort Mouse ID numbers are as follows:
4 homozygous mutant females (236416, 239049, 239054, 239056)
3 hemizygous mutant males (236410, 236411, 239082)
3 heterozygous mutant females (241941, 241942, 241943)
5 wild-type control males (236406, 236407, 236412, 239079, 239081)

300 Day Cohort Mouse ID numbers are as follows:
2 homozygous mutant females (236416, 239049)
2 hemizygous mutant males (236410, 236411)
2 heterozygous mutant females (241939, 241941)
2 wild-type control males (236406, 239079)

Values for the various analytes evaluated were generally similar between female homozygous mutant, male hemizygous mutant, female heterozygous control, and male wild-type control mice. Although variations in clinical chemistry values were present in some mice, they were not related to genotype and, thus, were not considered phenotypically relevant.

Gene 1623
Hematology

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

Blood samples from the following mice were evaluated by a complete blood count and differential cell count.

49 Day Cohort Mouse ID numbers are as follows:
3 homozygous mutant females (236396, 236398, 244787)
2 heterozygous mutant females (236395, 236397)
3 hemizygous mutant males (236401, 236405, 236409)
2 wild-type control males (236389, 236390)

90 Day Cohort Mouse ID numbers are as follows:
4 homozygous mutant females (236416, 239049, 239054, 239056)
4 heterozygous mutant females (241941, 241942, 258073, 258094)
4 hemizygous mutant males (236410, 236411, 239082, 258084)
4 wild-type control males (236406, 236407, 239079, 239081)

180 Day Cohort Mouse ID numbers are as follows:
3 homozygous mutant females (236416, 239049, 239056)
3 heterozygous mutant females (241941, 241942, 241943)
3 hemizygous mutant males (236410, 236411, 239082)
5 wild-type control males (236406, 236407, 236412, 239079, 239081)

300 Day Cohort Mouse ID numbers are as follows:
2 homozygous mutant females (236416, 239049)
2 heterozygous mutant females (241939, 241941)
2 hemizygous mutant males (236410, 236411)
2 wild-type control males (239079, 253247)

Although minor variations of hematological values were present in some mice, these changes were not related to genotype and, thus, were not considered phenotypically relevant.

Gene 1623
Physical Examination

There were no significant differences detected in the female homozygous or male hemizygous mutant mice when compared with age- and gender-matched heterozygous or 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 (236396, 236398, 236399)
2 heterozygous mutant females (236395, 236397)
3 hemizygous mutant males (236401, 236405, 236409)
2 wild-type control males (236389, 236390)

300 Day Cohort Mouse ID numbers are as follows:
2 homozygous mutant females (236416, 239049)
2 heterozygous mutant females (241939, 241941)
2 hemizygous mutant males (236410, 236411)
2 wild-type control males (236406, 239079)

Mice were examined in detail as follows: 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 the appropriate gender.)

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

Gene 1623
Aging Metrics

Changes related to genotype:

There were no other significant differences detected in the homozygous mutant females or hemizygous mutant males 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 (236416, 239049, 239054, 239056)
4 heterozygous mutant females (241939, 241941, 241942, 241943)
5 hemizygous mutant males (236410, 236411, 239075, 239082, 258084)
5 wild-type control males (236406, 236407, 236412, 239079, 239081)

90 Day Cohort Mouse ID numbers are as follows:
4 homozygous mutant females (236416, 239049, 239054, 239056)
4 heterozygous mutant females (241939, 241941, 241942, 241943)
5 hemizygous mutant males (236410, 236411, 239075, 239082, 258084)
5 wild-type control males (236406, 236407, 236412, 239079, 239081)

180 Day Cohort Mouse ID numbers are as follows:
4 homozygous mutant females (236416, 239049, 239054, 239056)
3 hemizygous mutant males (236410, 236411, 239082)
5 wild-type control males (236406, 236407, 236412, 239079, 239081)

300 Day Cohort Mouse ID numbers are as follows:
2 homozygous mutant females (239054, 239056)
2 heterozygous mutant females (241942, 241943)
2 hemizygous mutant males (239082, 258084)
4 wild-type control males (236406, 236412, 239079, 239081)

Body Weight and Length Findings:

When compared to age- and gender-matched wild-type control mice, body weight and body weight/body length ratio were low in one day hemizygous mutant male (258084) at 49, 90 and 300 days, and in the two 300 day homozygous mutant females.  The findings in the 300 day homozygous mutant females correlated with low body weight at necropsy examination. These findings were though to  be related to genotype.

Other 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.