• Asian-Australasian Journal of Animal Sciences
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• v.22 no.2
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• pp.168-173
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• 2009

Human follicle-stimulating hormone (hFSH) is a pituitary glycoprotein that regulates follicular development and ovulation. Clinically, hFSH has been used to induce follicular growth in infertile women. The hormone is composed of heterodimers, including a common ${\alpha}$ subunit among the gonadotropin family and a hormone-specific ${\beta}$ subunit. Since assembly of the heterodimer is a rate-limiting step in the production of functional hFSH, transgenic clone cows carrying a single-chain hFSH transgene may efficiently produce functional hormone. Genes encoding the ${\alpha}$ and ${\beta}$ subunits of hFSH were linked using the C-terminal peptide sequence from the ${\beta}$ subunit of human chorionic gonadotropin. Bovine fetal fibroblasts were transfected with the gene construct, including the goat ${\beta}$-casein promoter and a single-chain hFSH coding sequence. Transfected fibroblasts were transferred into enucleated oocytes, and individual nuclear transfer (NT) embryos developed to the blastocyst stage were analyzed for the transgene by polymerase chain reaction. Seventy eight blastocysts (30.8%) were developed from 259 reconstructed embryos. Among these blastocysts, the hFSH gene was detected in 70.8% (34/48) of the embryos. Subsequent transfer of hFSH-transgenic clone embryos to 31 recipients results in 11 (35.5%) early pregnancies. However, all fetuses were lost before reaching day 180 of gestation. The results from this study demonstrated that bovine NT embryos carrying single-chain hFSH could be produced, and further extensive studies in which NT embryos are transferred to more recipients may give rise to single chain hFSH-transgenic cows for biomedical applications.

• Korean Journal of Animal Reproduction
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• v.27 no.3
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• pp.197-206
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• 2003

hFSH (human follicle stimulating hormone) is heterodimer consisting of $\alpha$ and $\beta$ subunits. Since assembly of the both subunits in the cell is often the rate-limiting step in production of functional hormone, single-chain hormones have been engineered by genetically linking two different cDNA fragments with a linker sequence. Using retrovirus vector system, the resulting recombinant hFSH gene was transferred in CHO cells and chicken embryos, and the expression of the gene was investigated. In CHO cells, protein synthesis from the single-chain FSH gene was 17 fold higher than that from the heterodimeric counterpart. In the study of transgenic chickens, ten of the eleven chicks hatched from 62 embryos manupulated with recombinant retrovirus stock was determined to carry transgenic genes. RT-PCR analyses confirmed transcription of the single-chain FSH gene, however, no recombinant FSH was detected from the blood samples.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.4
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• pp.498-503
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• 2003

Luteinizing hormone as other glycoprotein hormones is characterized by a heterodimeric structure composed a common $\alpha$-subunit noncovalently linked to a specific $\beta$-subunit. The correct conformation of the heterodimer is important for efficient secretion, hormonal-specific post-translational modifications, receptor binding and signal transduction. To determine whether $\alpha$- and $\beta$- subunits can be synthesized as a single polypeptide chain (tethered-bLH and -bFSH) and also display biological activities, the tetheredbLH and -bFSH molecules were constructed and transfected into chinese hamster ovary (CHO-K1) cells. LH and FSH activities were assayed by using the human embryonic kidney (HEK) 293 cells expressing rat LH and FSH receptor genes. The tethered-bLH and - bFSH proteins were efficiently secreted and showed a similar activity to the dimeric bovine LH and FSH $\alpha$/$\beta$ wild type and native purified from bovine pituitary. The tethered-molecules can be permit development of potent new analogues that stimulate ovarian development. Taken together, a single-chain analog can also be constructed to include additional hormone-specific bioactive generating potentially efficacious compounds. These data indicate the potentiality of the single chain approach to further investigate structurefunction relationships of LH and FSH.

• Korean Journal of Animal Reproduction
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• v.26 no.4
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• pp.395-399
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• 2002

Human chorionic gonadotropin (hCG) is a member of the glycoprotein hormone family which includes FSH. hCG TSH. These hormone family is characterized by a heterodimeric structure composed a common $\alpha$-subunit noncovalently linked to a hormone specific $\beta$-subunit. To determine u and $\beta$ -subunits can be synthesized as a single polypeptide chain (tethered-hCG) and also display biological activity, the tethered-hCC and -FSH molecule by fusing the carboxyl terminus of the hCG $\beta$-subunit to the amino terminus of the $\alpha$-subunit was constructed. To determine the importance of $\alpha$ COOH -terminal amino acid, we also deleted the $\alpha$ COOH-terminal amino acids. The expressing vectors were transfected into CHO-K 1 cells. The tethered-wthCG and -wtFSH was efficiently secreted. The $\alpha$ Δ83hCG and $\alpha$ Δ 83FSH mutants had no secretion. These results are the first conclusive evidence that COOH-terminal amino acids are very important for secretion in human glycoprotein hormone $\alpha$-subunit. These results demonstrated that the $\alpha$ Δ83hCG and $\alpha$ Δ 83FSH mutants could be play a pivotal role in the secretion of tethered-molecule.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.54-54
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• 2001

Human chorionic gonadotropin (hCG) is a member of the glycoprotein hormone family which includes FSH, hCG, TSH. These hormone family is characterized by a heterodimeric structure composed a common $\alpha$-subunit noncovalently linked to a hormone specific $\beta$-subunit. The correct conformation of the heterodimer is also important for efficient secretion, hormone-specific post-translational modifications, receptor binding and signal transduciton. To determine $\alpha$ and $\beta$-subunits can be synthesized as a single polypeptide chain (tethered-hCG) and also display biological activity, the tethered-hCG molecule by fusing the carboxyl terminus of the hCG $\beta$-subunit to the amino terminus of the $\alpha$-subunit was constructed and transfected into chinese hamster ovary (CHO-K1) cells. We also constructed C-terminal deletion mutants (D9l, D89, D88, D87, D86, D84, D83) of single chain hCG to determine the biological function (secretion, LH-activity, receptor binding, cAMP production) of these mutants. Between six and eight stably transfected pools of cells expressing wild type and mutant hCGs were selected for neomycin resistant. The hCGs secreted by the stably transfected cells into serum-free media were collected and quantified by radioimmunoassay, as described in protocol (DPC(hCG IRMA). LH activity was in terms of testosterone production and aromatase activity in primary cultured rat Leydig cells. The tethered-wthCG was efficiently secreted and showed similar LH-like activity to the dimeric hCG. The D83hCG mutant was not detected in this assay. It is suggest that hCG C-terminal part is very important for hCG secretion. Now, we checking the LH-like activity of these mutant hCGs. These data indicate that the constructs of tethered molecule will be useful in the study of mutants that affect subunit association and/or secretion.

• Proceedings of the KSAR Conference
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• 2004.06a
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• pp.210-210
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• 2004

Equinechorionic gonadotropin(eCG) is a member of the glycoprotein hormone family which includes FSH, hCG, TSH. These hormone family is characterized by a heterodimeric structure composed a common α-subunit noncovalently linked to a hormone specific β-subunit. To determine a and β-subunits can be synthesized as a single polypeptide chain (tethered-eCG) and also display biological activity, the tethered-molecule by fusing the carboxyl terminus of the eCG β-subunit to the amino terminus of the α-subunit was constructed and transfected into chinese hamster ovary (CHO-K1) cells. (omitted)

• Proceedings of the KSAR Conference
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• 2000.10a
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• pp.10-12
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• 2000

Members of the glycoprotein family, which includes CG, LH, FSH and TSH, comprise two noncovalently linked $\alpha$- and $\beta$-subunits. Equine chorionic gonadotropin (eCG), known as PMSG, has a number of interesting and unique characteristics since it appears to be a single molecule that possesses both LH- and FSH-like activities in other species than the horse. This dual activity of eCG in heterologous species is of fundamental interest to the study of the structure-function relationships of gonadotropins and their receptors. CG and LH $\beta$ genes are different in primates. In horse, however, a single gene encodes both eCG and eLH $\beta$-subunits. The subunit mRNA levels seem to be independently regulated and their imbalance may account for differences in the quantities of $\alpha$ - and $\beta$ -subunits in the placenta and pituitary. The dual activities of eCG could be separated by removal of the N-linked oligosaccharide on the $\alpha$-subunit Asn 56 or CTP-associated O-linked oligosaccharides. The tethered-eCG was. efficiently secreted and showed similar LH-like activity to the dimeric eCG. Interestingly, the FSH-like activity of the tethered-eCG was increased markedly in comparison with the native and wild type eCG. These results also suggest that this molecular can implay particular models of FSH-like activity not LH-like activity in the eCG/indicate that the constructs of tethered molecule will be useful in the study of mutants that affect subunit association and/or secretion. A single-chain analog can also be constructed to include additional hormone-specific bioactive generating potentially efficacious compounds that have only FSH-like activity. The LH/CG receptor (LH/CGR), a membrane glycoprotein that is present on testicular Leydig cells and ovarian theca, granulosa, luteal, and interstitial cells, plays a pivotal role in the regulation of gonadal development and function in males as well as in nonpregnant and pregnant females. The LH/CGR is a member of the family of G protein-coupled receptors and its structure is predicted to consist of a large extracellular domain connected to a bundle of seven membrane-spanning a-helices. The LH/CGR phosphorylation can be induced with a phorbol ester, but not with a calcium ionophore. The truncated form of LHR also was down-regulated normally in response to hCG stimulation. In contrast, the cell lines expressing LHR-t63I or LHR-628, the two phosphorylation-negative receptor mutant, showed a delay in the early phase of hCG-induced desensitization, a complete loss of PMA-induced desensitization, and an increase in the rate of hCG-induced receptor down-regulation. These results clearly show that residues 632-653 in the C-terminal tail of the LHR are involved in PMA-induced desensitization, hCG-induced desensitization, and hCG-induced down-regulation. Recently, constitutively activating mutations of the receptor have been identified that are associated with familial male-precocious puberty. Cells expressing LHR-D556Y bind hCG with normal affinity, exhibit a 25-fold increase in basal cAMP and respond to hCG with a normal increase in cAMP accumulation. This mutation enhances the internalization of the free and agonist-occupied receptors ~2- and ~17-fold, respectively. We conclude that the state of activation of the LHR can modulate its basal and/or agonist-stimulated internalization. Since the internalization of hCG is involved in the termination of hCG actions, we suggest that the lack of responsiveness detected in cells expressing LHR-L435R is due to the fast rate of internalization of the bound hCG. This statement is supported by the finding that hCG responsiveness is restored when the cells are lysed and signal transduction is measured in a subcellular fraction (membranes) that cannot internalize the bound hormone.

• Korean Journal of Animal Reproduction
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• v.24 no.4
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• pp.357-364
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• 2000

Members of the glycoprotein family, which includes CG, LH, FSH and TSH, comprise two noncovalently linked $\alpha$- and $\beta$-subunits. Equine chorionic gonadotropin (eCG), known as PMSG, has a number of interesting and unique characteristics since it appears to be a single molecule that possesses both LH- and FSH-like activities in other species than the horse. This dual activity of eCG in heterologous species is of fundamental interest to the study of the structure-function relationships of gonadotropins and their receptors. CG and LH $\beta$ genes are different in primates. In horse, however, a single gene encodes both eCG and eLH $\beta$ -subunits. The subunit mRNA levels seem to be independently regulated and their imbalance may account for differences in the quantities of $\alpha$ - and $\beta$-subunits in the placenta and pituitary. The dual activities of eCG could be separated by removal of the N-linked oligosaccharide on the $\alpha$-subunit Asn 56 or CTP-associated O-linked oligosaccharides. The tethered-eCG was efficiently secreted and showed similar LH-like activity to the dimeric eCG. Interestingly, the FSH-like activity of the tethered-eCG was increased markedly in comparison with the native and wild type eCG. These results also suggest that this molecular can implay particular models of FSH-like activity not LH-like activity in the eCG/indicate that the constructs of tethered molecule will be useful in the study of mutants that affect subunit association and/or secretion. A single-chain analog can also be constructed to include additional hormone-specific bioactive generating potentially efficacious compounds that have only FSH-like activity. The LH/CG receptor (LH/CGR), a membrane glycoprotein that is present on testicular Leydig cells and ovarian theca, granulosa, luteal, and interstitial cells, plays a pivotal role in the regulation of gonadal development and function in males as well as in nonpregnant and pregnant females. The LH/CGR is a member of the family of G protein-coupled receptors and its structure is predicted to of a large extracellular domain connected to a bundle of seven membrane-spanning a-helices. The LH/CGR phosphorylation can be induced with a phorbol ester, but not with a calcium ionophore. The truncated form of LHR also was down-regulated normally in response to hCG stimulation. In contrast, the cell lines expressing LHR-t631 or LHR-628, the two phosphorylation-negative receptor mutant, showed a delay in the early phase of hCG-induced desensitization, a complete loss of PMA-induced desensitization, and an increase in the rate of hCG-induced receptor down-regulation. These results clearly show that residues 632~653 in the C-terminal tail of the LHR are involved in PMA-induced desensitization, hCG-induced desensitization, and hCG-induced down-regulation. Recently, constitutively activating mutations of the receptor have been identified that are associated with familial male-precocious puberty. Cells expressing LHR-D556Y bind hCG with normal affinity, exhibit a 25-fold increase in basal cAMP and respond to hCG with a normal increase in cAMP accumulation. This mutation enhances the internalization of the free and agoinst-occupied receptors ~2- and ~17- fold, respectively. We conclude that the state of activation of the LHR can modulate its basal and/or agonist-stimulated internalization. Since the internalization of hCG is involved in the termination of hCG actions, we suggest that the lack of responsiveness detected in cells expressing LHR-L435R is due to the fast rate of internalization of the bound hCG. This statement is supported by the finding that hCG responsiveness is restored when the cells are lysed and signal transduction is measured in a subcellular fraction (membranes) that cannot internalize the bound hormone.