The genetically engineered mice require special husbandry care and are mainly housed in Individually Ventilated Cage (IVC) systems and Static Micro Isolator Cages (SMIC) to minimize the risk for spreading undesirable microorganisms. However, the static micro isolation cage housing like SMIC are being replaced with IVC systems in many facilities due to a number of benefits like a higher density housing in limited space, better protection from biohazards and allergens and decreased work load due to decreased frequency of cage changing required in this system. The purpose of this study was to examine the reproductive performance of genetically engineered mice housed in individually ventilated cages (IVC) and Static Micro Isolator Cages (SMIC). When the B6C3-Tg (APPswe, PSEN1dE9) 85Dbo/Mmjax transgenic mice were housed in these two housing systems, the number of litters per dam, number of pups born per dam and number of pups weaned per dam were found to be slightly higher in the IVC as compared to the SMIC but the difference was not significant (P<0.05). In case of Growth Associated Protein 43 (GAP-43) knockout mice, the number of litters born per dam and the number of pups born per dam were marginally higher in the IVC as compared to those housed in SMIC but the difference was not significant (P<0.05). Only the number of pups weaned per dam were found to be significantly higher as compared to those housed in the SMIC system at P<0.05.
Allergens ; Animals ; GAP-43 Protein ; Hazardous Substances ; Housing* ; Mice* ; Mice, Knockout ; Mice, Transgenic

Telomeres serve a critical role in maintenance of genomic stability in all eukaryotes, from yeast to human. The maintenance of telomeres is achieved by the telomerase complex, which is largely composed of telomerase reverse transcriptase (TERT) and telomerase RNA component (TERC). A variety of mouse models have provided valuable insights into the relationship between the telomerase complex and telomere dysfunction at the organismal level and helped understand their biological significance in human. Recently, in addition to its role in maintenance of the telomeres, novel functions of the telomerase complex have been emerging. In this review, studies of all gene-targeted or transgenic mouse models so far generated for telomerase and telomere biology are comprehensively described, and potential novel functions of telomerase are briefly discussed
Animals ; Cell Aging/*physiology ; Mice ; Mice, Knockout ; Mice, Transgenic ; Models, Animal ; RNA/*metabolism ; Telomerase/*metabolism ; Telomere/*metabolism

OBJECTIVE: To study the effect of Wdr1 deletion in germ cells on ovarian function of mice. METHODS: Oocyte-specific gene knockout mouse model was constructed by crossing Wdr1female mice with Cre recombinase transgenic male mice which was driven by a germ cell-specific promoter. Wdr1; Ddx4-Cre mice and control mice were sacrificed at 14 days, 28 days and 4 months after birth, whose ovaries were subjected to photography, paraffin sectioning and Hematoxylin-Eosin (HE) staining. The ovarian volume and follicular numbers were recorded at various time points. RESULTS: The ovarian volume of Wdr1 ; Ddx4-Cre mice was slightly lower than that of the controls at 14 days. HE staining showed that primordial follicles, primary follicles and secondary follicles were slightly reduced compared with the control mice at 14 days. The ovarian volume of Wdr1 ; Ddx4-Cre mice was significantly lower than that of the control mice at 28 days and 4 months. HE staining showed that all developmental follicles were significantly reduced compared with the control mice. CONCLUSION Wdr1 gene deletion in germ cells can influence early ovarian function of mice and lead to premature ovarian failure.
Animals ; Female ; Germ Cells ; Male ; Mice ; Mice, Knockout ; Mice, Transgenic ; Microfilament Proteins ; genetics ; Oocytes ; Ovarian Follicle ; physiopathology

OBJECTIVE: To construct a HIV-1 gp120 transgenic mice (gp120 Tg) with vimentin (VIM) gene knockout. METHODS: Female HIV-1 gp120 Tg mice were mated to VIM heterozygote mice (F0). All the offspring mice were derived from these original founders so that both genotypes had the same mixed genetic background. The F1 mice were bred to generate of VIM, VIM, VIM/gp120 Tg and VIM/gp120 Tg mice. PCR was performed for genotyping of the mice, and the expressions of VIM and gp120 in the brain tissues were examined using immunoblotting. RESULTS: The results of PCR showed the presence of the target bands in VIM, VIM, VIM/gp120 Tg and VIM/gp120 Tg mice. In VIM/gp120 Tg mice, gp120 expression was detected throughout the brain regions while no VIM expression was detected. CONCLUSIONS We generated gp120 transgenic mouse models with VIM gene knockout, which facilitate the exploration of the role of VIM in gp120-induced neurotoxicity.
Animals ; Brain ; Disease Models, Animal ; Female ; HIV Envelope Protein gp120 ; HIV-1 ; Mice ; Mice, Knockout ; Mice, Transgenic ; Vimentin

OBJECTIVE: To construct a HIV-1 gp120 transgenic mouse model (gp120) with 7 nicotinic acetylcholine receptor (7nAChR) gene knockout. METHODS: The 7nAChR gene knockout mice (7R) were crossed with HIV-1gp120 transgenic mice (gp120) to generate F1 generation mice. We selected the F1 mice with the genotype of 7R/gp120 to mate to obtain the F2 mice. The genotypes of the F3 mice were identified by PCR, and the protein expressions in the double transgenic animal model was analyzed by immunohistochemistry. BV2 cells were treated with gp120 protein and 7nAChR inhibitor, and the expressions of IL-1β and TNF- were detected using ELISA. RESULTS: The results of PCR showed the bands of the expected size in F3 mice. Two F3 mice with successful double gene editing (7R/gp120) were obtained, and immunohistochemistry showed that the brain tissue of the mice did not express 7 nAChR but with high gp120 protein expression. In the cell experiment, treatment with gp120 promoted the secretion of IL-1β and TNF- in BV2 cells, while inhibition of 7nAChR significantly decreased the expression of IL-1β and TNF- ( < 0.001). CONCLUSIONS By mating gp120 Tg mice with 7R mice, we obtained gp120 transgenic mice with 7nAChR gene deletion, which serve as a new animal model for exploring the role of 7nAChR in gp120-induced neurotoxicity.
Animals ; Disease Models, Animal ; Glycoproteins ; Mice ; Mice, Knockout ; Mice, Transgenic ; Tumor Necrosis Factor-alpha ; alpha7 Nicotinic Acetylcholine Receptor ; metabolism

The pathogenesis of psoriasis recently made great advancement due to the introduction of transgenic mouse model. K14-VEGF transgenic mouse showed many of the cellular and molecular features of psoriasis, including angiogenesis in dermis, altered epidermal proliferation and differentiation. Psoriasis of early onset and severe disease showed significantly increased frequency of the +405CC genotype and the C allele. Transgenic mice with keratinocytes expressing active Stat3 (K5. Stat3C mice) developed a skin phenotype closely resembling psoriasis. Stat 3 may link activated keratinocytes and immunocytes required for development of psoriasis. More recently, a novel mouse model with epidermal specific double-knockout of the c-Jun and JunB genes showed developments of psoriasis-like skin phenotype and arthritic lesions. All these data provided more profound understanding in pathogenesis and therapy of psoriasis.
Animals ; Disease Models, Animal ; Humans ; Keratinocytes ; metabolism ; pathology ; Mice ; Mice, Knockout ; Mice, Transgenic ; Psoriasis ; etiology ; genetics ; pathology ; STAT3 Transcription Factor ; genetics ; metabolism ; Vascular Endothelial Growth Factors ; genetics ; metabolism

SRG3 (SWI3-related gene) is a core subunit of mouse SWI/SNF complex and is known to play a critical role in stabilizing the SWI/SNF complex by attenuating its proteasomal degradation. SWI/SNF chromatin remodeling complex is reported to act as an important endogenous regulator in the proliferation and differentiation of mammalian neural stem cells. Because limited expression of SRG3 occurs in the brain and thymus during mouse embryogenesis, it was hypothesized that the altered SRG3 expression level might affect the process of adult hippocampal neurogenesis. Due to the embryonic lethality of homozygous knockout mice, this study focuses on dissecting the effect of overexpressed SRG3 on adult hippocampal neurogenesis. The BrdU incorporation assay, immunostaing with neuronal markers for each differentiation stage, and imunoblotting analysis with intracellular molecules involved in survival in adult hippocampal neurogenesis found no alteration, suggesting that the overexpression of SRG3 protein in mature neurons had no effect on the entire process of adult hippocampal neurogenesis including proliferation, differentiation, and survival.
Adult ; Animals ; Brain ; Bromodeoxyuridine ; Chromatin Assembly and Disassembly ; Embryonic Development ; Female ; Humans ; Mice ; Mice, Knockout ; Mice, Transgenic ; Neural Stem Cells ; Neurogenesis ; Neurons ; Pregnancy ; Thymus Gland

OBJECTIVETo generate transgenic mice of NKCC1 +/- (heterozygous) and NKCC1 +/+ (wild-type) that have a targeted disruption in the NKCC1 gene in order to investigate the relationship of one copy of NKCC1 gene (NKCC1 +/-) and age-related hearing loss (AHL) and to study the possible pathogenesis of AHL METHODS: Auditory function of NKCC1 +/- mice was detected regularly by auditory brain response (ABR) and endocochlear potential (EP). Morphology of cochlea was observed by scanning electron microscope and content of NKCC1 protein was detected by Western blot.

RESULTSThe mean value for ABR thresholds was elevated in NKCC1 +/- mice more than that of NKCC1 +/+ mice (P < 0.01). A progression of age-related hearing loss was found in NKCC1 +/- mice. Compared with younger NKCC1 +/- mice, the mean value for ABR thresholds in aged NKCC1 +/- mice was significantly increased (P < 0.05). The EP of NKCC1 +/- aged mice was also significantly decreased more than that of the younger NKCC1 +/+ mice (P < 0.05). And content of NKCC1 protein were reduced with the growth of the age. The scanning electron microscope showed a kind of scattered punctiform absence of outer hair cells in elder NKCC1 +/- mice cochlea.

CONCLUSIONSNKCC1 gene maybe takes part in the pathogenesis of AHL. Mice that expressed only one copy of NKCC1 could lead to AHL. AHL may be correlative with the amounts of NKCC1 protein and its function and also with the loss of outer hair cells perhaps.

Age Factors ; Aging ; genetics ; physiology ; Animals ; Hearing Disorders ; etiology ; genetics ; Heterozygote ; Mice ; Mice, Knockout ; Mice, Transgenic ; Sodium-Potassium-Chloride Symporters ; genetics ; Solute Carrier Family 12, Member 2

OBJECTIVETo generate the skeletal muscle-specific transforming growth factor beta receptor II (TbetaR II) gene knockout mice for the research on the function of the TbetaR II gene in skeletal muscles.

METHODSTbetaR II (flox/flox) mice were generated using embryonic stem cell technology. The MCK-Cre mice were engineered containing Cre recombinase under the control of creatine kinase (MCK) muscle-specific promoter. TbetaR II (flox/flox) mice were crossed with MCK-Cre mice generating TbetaR II (flox/flox)/MCK-Cre double Tg mice. And then, TbetaR II (flox/wt) /MCK-Cre(+) double Tg mice were crossed with TbetaR II (flox/flox) mice to generate TbetaR II (flox/flox)/MCK- Cre(+) mice genetically ablating TbetaR II in cre-expressing skeletal muscle cells.

RESULTSAs predicted, mice lacking TbetaR II by gene targeting in skeletal muscles were generated first in the world using Cre/loxP system. TbetaR II null mutant mice were viable, fertile and showed apparently normal development.

Animals ; Mice ; Mice, Knockout ; Mice, Transgenic ; Muscle, Skeletal ; metabolism ; Protein-Serine-Threonine Kinases ; genetics ; metabolism ; Receptors, Transforming Growth Factor beta ; genetics ; metabolism ; Recombination, Genetic ; Signal Transduction

OBJECTIVE: To investigate the role of tacrolimus-binding protein 38 (FKBP38) in follicle development and the mechanism by which Fkbp38 gene deletion causes premature ovarian insufficiency (POI). METHODS: The Cre-loxp system was used to construct oocyte-specific Fkbp38 knockout transgenic mice. The genotype of the transgenic mice was identified using PCR, and the expression of FKBP38 in the oocytes was verified. The numbers of primordial follicles, primary follicles, secondary follicles and antral follicles in Fkbp38 knockout mice and non-transgenic littermate control mice were counted with HE staining under a microscope for analyzing the effect of Fkbp38 deletion on follicular development. The fertility and serum sex hormone levels of the mice were determined by reproduction experiments and ELISA to assess ovarian function. Ovarian granulosa cell apoptosis of the mice was assessed using TUNEL assay. The activity of the downstream target protein of phosphorylated ribosomal S6 (PS6) of mTOR signaling pathway was detected, and the expressions of BCL-2 and BAX proteins were determined using immunofluorescence assay for assessing oocyte development in the mice. RESULTS: The oocyte-specific Fkbp38 knockout transgenic mouse model was successfully constructed, which showed decreased fertility, disordered sex hormone levels, and significantly reduced primordial follicles, primary follicles and secondary follicles in the ovary (P < 0.05), demonstrating POI-like changes. Compared with the control mice, oocyte-specific Fkbp38 knockout caused activation of the mTOR signaling pathway, significantly increased apoptosis of the granulosa cells, and obviously increased the BAX/BCL- 2 ratio by increasing BAX expression and reducing BCL-2 expression in the oocytes (P < 0.05). CONCLUSION FKBP38 plays an important role in follicle development, and Fkbp38 gene deletion in mice causes POI possibly by activating the mTOR signaling pathway and inducing granulosa cell apoptosis.
Female ; Humans ; Mice ; Animals ; Primary Ovarian Insufficiency/genetics* ; Apoptosis ; Signal Transduction ; Proto-Oncogene Proteins c-bcl-2 ; Granulosa Cells ; Mice, Transgenic ; Mice, Knockout ; TOR Serine-Threonine Kinases