• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.6
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• pp.565-571
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• 2000

Mixed primers based on the high sequence homology of selected regions of known connexins (Cxs) was used for PCR reaction. A full-length connexin cDNA of sweetfish (Plecoglossus altivelis) was cloned by rapid amplification of cDNA 5'and (5'RACE) and 3'RACE method. When compared to other known Cx sequences, homology of sweetfish Cx cDNA to Atlantic croaker, Mycropogonias undulatus Cx32.7, bovine, Bos taurus Cx44 and Atlantic croaker Cx32.2 were $63.8{\%},\;61.6{\%}\;and\;56.7{\%}$, respectively. This cDNA encoded 308 amino acids (35,028 dalton) and named as sweetfish Cx35. Hydropathicity analysis of predicted amino acid sequences indicated that sweetfish Cx35 have four major hydrophobic regions and four major hydrophilic regions, suggesting its topology is similar to that of known Cxs. The presence of a tfical Cx consensus sequences were identified in each of the extracellular loops (first loop and second loop).

• Development and Reproduction
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• v.20 no.4
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• pp.349-357
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• 2016

The present research was chiefly designed to determine the effect of the treatment of estrogenic agonist, estradiol benzoate (EB), or antiandrogenic compound, flutamide (Flu), at the weaning age on the expression of connexin (Cx) isoforms in the caudal epididymis of adult male rat. Animals were subcutaneously administrated with a single shot of either EB at a low-dose ($0.015{\mu}g$ of EB/kg body weight (BW)) or a high-dose ($1.5{\mu}g$ of EB/kg BW) or Flu at a low-dose ($500{\mu}g$ of EB/kg BW) or a high-dose (5 mg of EB/kg BW). Expressional changes of Cx isoforms in the adult caudal epididymis were examined by quantitative real-time PCR analysis. The treatment of a low-dose EB caused significant increases of Cx30.3, Cx31, Cx32, and Cx43 transcript levels but reduction of Cx31.1, Cx37, and Cx45 expression. Exposure to a high-dose EB resulted in very close responses observed in a low-dose EB treatment, except no significant expressional change of Cx37 and a significant induction of Cx40. Expression of all Cx isoforms, except Cx45, was significantly increased by a low-dose Flu treatment. Expressional increases of all Cx isoforms were detected by a high-dose Flu treatment. The current study demonstrates that a single exposure to estrogenic or antiandrogenic compound during the early postnatal developmental period is sufficient to disrupt normal expression of Cx isoforms in the adult caudal epididymis.

• Development and Reproduction
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• v.19 no.2
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• pp.69-77
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• 2015

Cell-cell direct communication through channel-forming molecules, connexin (Cx), is essential for a tissue to exchange signaling molecules between neighboring cells and establish unique functional characteristics during postnatal development. The corpus epididymis is a well-known androgen-responsive tissue and involves in proper sperm maturation. In the present research, it was attempted to determine if expression of Cx isoforms in the corpus epididymis in the adult is modulated by exposure to estrogenic or anti-androgenic compound during the early postnatal period. The neonatal male rats at 7 days of age were subcutaneously injected by estradiol benzoate (EB) at low-dose ($0.015{\mu}g/kg$ body weight) or high-dose ($1.5{\mu}g/kg$ body weight) or flutamide (Flu) at low-dose ($500{\mu}g/kg$ body weight) or high-dose (50 mg/kg body weight). The corpus epididymis collected at 4 months of age was subjected to evaluate expressional changes of Cx isoforms by quantitative real-time PCR. Treatment of low-dose EB resulted in increases of Cx32, Cx37, and Cx45 transcript levels, while exposure to high-dose EB decreased expression of Cx26, Cx30.3, Cx31, Cx31.1, Cx32, Cx40, Cx43, and Cx45. Treatments of Flu caused significant decreases of expression of all examined Cx isoforms, except Cx37 and Cx43 shown no expressional change with high-dose Flu treatment. These findings imply that expression of most Cx isoforms present in the corpus epididymis would be transcriptionally regulated by actions of androgen and/or estrogen during postnatal period.

• Development and Reproduction
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• v.5 no.2
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• pp.115-122
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• 2001

Production of a mature oocyte is a complex process that requires the close association between oocyte and follicular cells. The present study was conducted to investigate the difference between oocytes with and without close junctional communication with cumulus cells and the involvement of two connexins(CXs) in the interactions. Follicles at different sizes(small: 200～400 ㎛; large:>450 ㎛) were mechanically isolated from PMSG-primed mouse ovaries, and punctured to get cumulus-oocyte complex(COC). Oocytes were released themselves(denuded), with partially attached(partial), or with tightly attached(intact) cumulus cells. Maturation and fertilization capacity of the COCs were measured. Expression of CX 37 and CX 43 was examined by RT-PCR and in situ hybridization. The ratio between intact COC and denude/partial oocytes was 30％(SI) and 70％(SPD) in small follicles, while 55％(LI) and 45％(LPD) in large follicles, respectively. Maturation and fertilization rates of the released oocytes were similar among SI, LPD, LI groups, but those were significantly lower in SPD oocytes. In oocytes, CX 37 was the major CX and CX 43 was not expressed, whereas in the cumulus cells, CX 43 was the major, and CX 37 was the next. Results of the present study suggest that 1) immature oocytes from small follicles with intact cell-to-cell communication with cumulus have the similar quality to that of the oocytes from larger follicles, 2) gap junction between oocyte and cumulus cells may be the heterotypic channel, and 3) we could not explain the difference in the cell-to-cell communication between intact and partial/denuded COCs through the expression of the two CXs.