• Molecules and Cells
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• v.41 no.7
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• pp.631-638
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• 2018

Spermatogonial stem cells (SSCs) derived from mouse testis are unipotent in regard of spermatogenesis. Our previous study demonstrated that SSCs can be fully reprogrammed into pluripotent stem cells, so called germline-derived pluripotent stem cells (gPS cells), on feeder cells (mouse embryonic fibroblasts), which supports SSC proliferation and induction of pluripotency. Because of an uncontrollable microenvironment caused by interactions with feeder cells, feeder-based SSC reprogramming is not suitable for elucidation of the self-reprogramming mechanism by which SSCs are converted into pluripotent stem cells. Recently, we have established a Matrigel-based SSC expansion culture system that allows longterm SSC proliferation without mouse embryonic fibroblast support. In this study, we developed a new feeder-free SSC self-reprogramming protocol based on the Matrigel-based culture system. The gPS cells generated using a feeder-free reprogramming system showed pluripotency at the molecular and cellular levels. The differentiation potential of gPS cells was confirmed in vitro and in vivo. Our study shows for the first time that the induction of SSC pluripotency can be achieved without feeder cells. The newly developed feeder-free self-reprogramming system could be a useful tool to reveal the mechanism by which unipotent cells are self-reprogrammed into pluripotent stem cells.

• Biomolecules & Therapeutics
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• v.18 no.3
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• pp.257-261
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• 2010

While it's been shown that arsenic impairs male reproductive function, it remains unclear whether the mechanism involves an effect on testosterone (T) production. We examined plasma T and luteinizing hormone (LH) levels in mice given water containing either 20 or 40 mg/L sodium arsenite (SA). The plasma T levels were lower in SA-treated mice than in controls and correlated well with testicular T levels within individuals. However, SA treatment did not significantly affect plasma LH levels. The ratio of plasma T to LH was reduced by the treatment with 40 mg/L SA. These results suggest arsenic-induced defect in testicular testosterone production in mice.

• 대한생식의학회:학술대회논문집
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• 2004.11a
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• pp.33-33
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• 2004

• Journal of Microbiology
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• v.34 no.4
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• pp.311-315
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• 1996

The retroviral Gag polyprotein directs the assembly of virion particles and plays an important role in some events after entry into a host cell. The Gag polyprotein of a virus mixture is responsible for inducing murine acquired immunodeficiency syndrome (MAIDS) when injected into susceptible strains of mice. In order to identify the host cellular proteins which interact with the MAIDS virus Gag proteins and possibly mediate the function of the Gag proteins, mouse T-cell leukemic cDNA expression library was screened using the yeast GAL4 two hybrid system. Of 11 individual positive clones, the clone Y1 was selected for the study of protein-protein interaction. Its DNA sequence revealed that it was an exact match to the murine SH3 domain-containing protein SH3P8. It is expressed as 2.4 kbp transcripts in testis at higher levels and in various tissues tested at lower levels. Glutathione S-transferase-Y1 fusion protein binds tightly to $Pr60^{def-gag}$ as well as $Pr65^{eco-gag}$.

• 대한생식의학회:학술대회논문집
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• 2006.06a
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• pp.170.1-170.1
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• 2006

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.10
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• pp.1398-1406
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• 2016

In general, the seminiferous tubule basement membrane (STBM), comprising laminin, collagen IV, perlecan, and entactin, plays an important role in self-renewal and spermatogenesis of spermatogonial stem cells (SSCs) in the testis. However, among the diverse extracellular matrix (ECM) proteins constituting the STBM, the mechanism by which each regulates SSC fate has yet to be revealed. Accordingly, we investigated the effects of various ECM proteins on the maintenance of the undifferentiated state of SSCs in pigs. First, an extracellular signaling-free culture system was optimized, and alkaline phosphatase (AP) activity and transcriptional regulation of SSC-specific genes were analyzed in porcine SSCs (pSSCs) cultured for 1, 3, and 5 days on non-, laminin- and collagen IV-coated Petri dishes in the optimized culture system. The microenvironment consisting of glial cell-derived neurotrophic factor (GDNF)-supplemented mouse embryonic stem cell culture medium (mESCCM) (GDNF-mESCCM) demonstrated the highest efficiency in the maintenance of AP activity. Moreover, under the established extracellular signaling-free microenvironment, effective maintenance of AP activity and SSC-specific gene expression was detected in pSSCs experiencing laminin-derived signaling. From these results, we believe that laminin can serve as an extracellular niche factor required for the in vitro maintenance of undifferentiated pSSCs in the establishment of the pSSC culture system.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2006.11a
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• pp.43-58
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• 2006

As a bioreactor, bird has proved to be most efficient system for producing useful therapeutic proteins. More than half of the egg white protein content derives from the ovalbumin gene with four other proteins(lysozyme, ovomucoid, ovomucin and conalbumin) present at levels of 50 milligrams or greater. And the naturally sterile egg also contains egg white protein at high concentration allowing for a long shelf life of recombinant protein without loss in activity. In spite of these advantages, transgenic procedures for the bird have lagged far behind because of its complex process of fertilized egg and developmental differences. Recently, a system to transplant mouse testis cells from a fertile donor male to the seminiferous tubules of an infertile recipient male has been developed. Spermatogenesis is generated from transplanted cells, and recipients are capable of transmitting the donor haplotype to progeny. After transplantation, primitive donor spermatogonia migrate to the basement membrane of recipient seminiferous tubules and begin proliferating. Eventually, these cells establish stable colonies with a characteristic appearance, which expands and produces differentiating germ cells, including mature spermatozoa. Thus, the transplanted cells self-renew and produce progeny that differentiate into fully functional spermatozoa. In this study, to develop an alternative system of germline chimera production that operates via the testes rather than through developing embryos, the spermatogonial stem cell techniques were applied. This system consisted of isolation and in vitro-culture of chicken testicular cells, transfer of in vitro-maintained cells into heterologous testes, production of germline chimeras and confirmation of germline transmission for evaluating production of heterologous, functional spermatozoa.

• Animal cells and systems
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• v.2 no.4
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• pp.495-500
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• 1998

D-type G1 cyclins are known to be crucial for the progression of mitotic cell cycle in mammals. Although many studies have been performed to elucidate the roles of D-type cyclins, it is largely unknown whether D-type cyclins are directly involved in the regulation of meiotic germ cell development. In the present study, we examined the expression patterns of D-type cyclins (cyclin D1 and D3) during male germ cell development by northern blot and in situ Hybridization analyses. In the adult testes, we detected a 4.2 kb cyclin D1 mRNA and two different sizes (2.3 kb and 1.8 kb) of cyclinD3 mRNAs. The short form of the cyclin D3 transcript was testis-specific. Along with the testicular development, expression of cyclin D3 mRNA was increased whereas cyclin D1 mRNA was gradually decreased. in situ hybridization study also revealed that the expression of cyclin D3 was restricted to the postmeiotic germ cells. Furthermore, the 2.3 kb transcript was highly expressed in the round spermatids and decreased in the elongated spermatids/residual bodies, while the 1.8 kb transcript was expressed in elongated spermatids/residual bodies more abundantly. Sucrose-gradient separation of polysomal RNA fractions demonstrated that some portions of the 2.3 kb transcript are translationally active, while the 1.8 kb transcript is likely to be inactive. Taken together, the present data suggest a functional importance of cyclin D3 expression in the differentiated postmeiotic male germ cells.

• Development and Reproduction
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• v.18 no.4
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• pp.301-309
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• 2014

Nesfatin-1, an anorexic nucleobindin-2 (NUCB2)-derived hypothalamic peptide, controls appetite and energy metabolism. Recent studies show that nesfatin-1/NUCB2 is expressed not only in the brain but also in gastric and adipose tissues. Thus, we investigated the distributions of nesfatin-1/NUCB2 in various tissues of male and female mice by real-time PCR, western blotting, and immunohistochemical staining. Real-time PCR analyses showed that NUCB2 mRNA was predominantly expressed in the pituitary and at lower levels in the hypothalamus, spleen, thymus, heart, liver, and muscle of both male and female mice. Expression was much higher in reproductive organs, such as the testis, epididymis, ovary, and uterus, than in the hypothalamus. Western blot analysis of the nesfatin-1 protein level showed similar results to the real-time PCR analyses in both male and female mice. These results suggest that nesfatin-1/NUCB2 have widespread physiological effects in endocrine and non-endocrine organs. In addition, immunohistochemical staining revealed that nesfatin-1 was localized in interstitial cells, including Leydig cells and in the columnar epithelium of the epididymis. Nesfatin-1 was also expressed in theca cells and interstitial cells in the ovary and in epithelial cells of the endometrium and uterine glands in the uterus. These results suggest that nesfatin-1 is a novel potent regulator of steroidogenesis and gonadal function in male and female reproductive organs. Further studies are required to elucidate the functions of nesfatin-1 in various organs of male and female mice.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.6
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• pp.447-453
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• 2006

Toxicity of two species of puffer fish, Takifugu porphyreus and Takifugu rubripes, collected from coastal regions of Korea, was determined using a mouse bioassay, In T. porphyreus, the proportion of toxic specimens containing ${\ge}$ 10 MU/g was 58.3% for the ovary, 32.6% for the skin, 12.0% for the gallbladder, 11.6% for the liver and intestine, and 9.3% for the fin; no toxicity was detected in the muscle and testis using the mouse bioassay. The highest toxin levels were 531 MU/g in the liver, 253 MU/g in the intestine, 136 MU/g in the gallbladder, 118 MU/g in the skin, 116 MU/g in the ovary, and 108 MU/g in the fin. The skin, which is used for human consumption, showed significantly high toxicity with an average of $11{\pm}3\;(mean{\pm}SE) MU/g$. Takifugu porphyreus toxicity also exhibited remarkable regional variation. In T. rubripes, the proportion of toxic specimens was 25.0% for the ovary, 15.8% for the liver, 11.1% for the gallbladder, and 5.3% for the fin and intestine; no toxicity was detected in the muscle, skin, or testis. Among the organs, the highest toxin levels were 228 MU/g in the ovary, followed by 112 MU/g in the liver, 28 MU/g in the gallbladder, 18 MU/g in the intestine, 11 MU/g in the fin, and 8 MU/g in the skin. Thus, we found acceptable toxin levels in the edible muscle and skin of T. rubripes and in the muscle of T. porphyreus. However, the skin of T. porphyreus, which showed significantly high toxicity, requires special attention when used for human consumption.