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Development of multidrug resistance type I Cmdr1 expression in chicken embryonic gonads
Abstract:
A primary role of P-glycoprotein (P-gp), encoded by the multidrug resistance type I gene, is to protect against naturally occurring xenotoxics. Recently, the preferential expression of chicken multidrug resistance type I (Cmdr1) was identified in the embryonic gonads during the early periods of development. Here we investigated the expression of Cmdr1 and P-gp in the gonads during embryogenesis, and compared to that in the ovarian follicles of domestic hens (Gallus gallus). As revealed by immunohistochemistry, P-gp was highly expressed in theca cells of mature follicles, whereas the expression was low in immature follicles. Immunohistochemical analysis showed that expression of Cmdr1-type P-gp was very low in embryonic gonads. Cmdr1 mRNA was undetectable in the gonads of 5-day embryos (E5) by RT-PCR, whereas Cmdr1 mRNA was significantly detectable in the developing gonads at E9 and E21. In the testicular tissues, germ cells were distributed along developing seminiferous cords as identified by a specific marker gene, whereas Cmdr1-type P-gp positive cells were observed evenly on testicular tissues. Collectively, it is concluded that Cmdr1 expression is initiated in the chicken ovary and testis after sexual differentiation, but expression of Cmdr1-type P-gp is very low through embryogenesis.
Insights
Chicken multidrug resistance type I (Cmdr1) and P-glycoprotein (P-gp) expression in embryonic gonads was investigated. Cmdr1 mRNA was detected after sexual differentiation, but P-gp expression remained low throughout embryogenesis.
Area of Science:
- Developmental Biology
- Molecular Biology
- Genetics
Background:
- P-glycoprotein (P-gp) protects against xenotoxics.
- Chicken multidrug resistance type I (Cmdr1) is preferentially expressed in embryonic gonads.
- Understanding Cmdr1 and P-gp expression is crucial for avian reproductive development.
Purpose of the Study:
- To investigate Cmdr1 and P-gp expression in chicken embryonic gonads.
- To compare expression patterns with ovarian follicles in domestic hens (Gallus gallus).
- To determine the developmental timing of Cmdr1 and P-gp expression during embryogenesis.
Main Methods:
- Immunohistochemistry was used to detect P-gp protein expression.
- Reverse transcription polymerase chain reaction (RT-PCR) was employed to analyze Cmdr1 mRNA levels.
- Expression was examined in embryonic gonads at different developmental stages (E5, E9, E21) and in ovarian follicles.
Main Results:
- P-gp showed high expression in theca cells of mature ovarian follicles, but low expression in immature follicles.
- Cmdr1-type P-gp expression was very low in embryonic gonads throughout development.
- Cmdr1 mRNA was undetectable at E5 but significantly detectable at E9 and E21 in developing gonads.
- Cmdr1-type P-gp positive cells were observed evenly in testicular tissues.
Conclusions:
- Cmdr1 expression initiates in chicken ovary and testis after sexual differentiation.
- Cmdr1-type P-gp expression is notably low during chicken gonad embryogenesis.
- These findings provide insights into the role of P-gp during avian reproductive development.
