外源激素处理后家蚕吡哆醛激酶和磷酸吡哆醇氧化酶转录水平的变化

Changes in the transcriptional levels of pyridoxal kinase and pyridoxine-5’-phosphate oxidase post exogenous hormone treatment in the silkworm,Bombyx mori

【目的】研究家蚕Bombyx mori经蜕皮激素（20-hydroxyecdysone,20-E）和保幼激素类似物（juvenile hormone analogue,JHA）处理后引起吡哆醛激酶（pyridoxal kinase,PLK）和磷酸吡哆醇氧化酶（pyridoxine-5＇-phosphate oxidase,PNPO）的转录水平变化,为进一步研究激素对蚕体营养代谢等工作奠定基础。【方法】以20-E和JHA分别喂食不同发育时期（5龄第1,3和5天）的家蚕幼虫,以喂食蒸馏水的家蚕为对照,采用实时荧光定量PCR（realtime quantitative PCR）方法在处理后24和48 h对各组幼虫后部丝腺中PLP合成酶PLK和PNPO的转录水平进行分析。【结果】5龄第1天幼虫经20-E处理24和48 h后,PLK和PNPO的转录水平出现上调且与对照的差异达到极显著（P〈0.01）;5龄第3天幼虫经20-E处理,PLK的转录水平在48 h出现下调且与对照的差异达到显著（P〈0.05）,PNPO的转录水平在24和48 h均出现上调且与对照的差异达到极显著（P〈0.01）;5龄第5天幼虫经20-E处理后PLK和PNPO的转录水平无变化。5龄第1天幼虫经JHA处理后PLK和PNPO的转录水平未受到影响;5龄第3天幼虫经JHA处理后,PLK的转录水平在48 h出现显著下调且与对照的差异达到显著（P〈0.05）,PNPO的转录水平在24和48 h后均出现显著下调且与对照的差异达到极显著（P〈0.05）;5龄第5天幼虫经JHA处理24和48 h后,PLK和PNPO的转录水平出现下调且与对照的差异达到极显著（P〈0.01）。【结论】20-E和JHA显著影响家蚕5龄幼虫PLK和PNPO的转录水平,20-E提高5龄前期家蚕PLK和PNPO的转录水平,JHA降低5龄后期它们的转录水平,为深入研究激素对VB_6的调控奠定基础。

[ Aim ] To further research the hormone regulation of nutrition metabolism, we analyzed the transcription levels of pyridoxal kinase （PLK） and pyridoxine-5 ＇-phosphate oxidase （PNPO） of the silkworm, Bornbyx mori, treated with 20-hydroxyecdysone （20-E） and juvenile hormone analogue （JHA）. [Methods] The day-l, day-3 and day-5 5th instar larvae of B. mori were fed with 20-E or JHA, and those fed on distilled water were used as the control. We assayed the transcriptional levels of PLK and PNPO in silk glands of the treated larvae at 24 and 48 h post treatment by using real-time quantitative PCR. [Results] In the day-1 5th instar larvae treated with 20-E for 24 and 48 h, respectively, the transcriptional levels of PLK and PNPO significantly increased compared with the control （P 〈 0.01 ）. In the day-3 5th instar larvae treated by 20-E, the transcriptional level of PLK decreased compared with the control at 48 h after treatment （ P 〈 0.05 ）, whereas the transcriptional level of PNPO significantly increased compared with the control at 24 and 48 h after treatment （ P 〈 0.01 ）. In the day-5 5th instar larvae treated with 20-E, the transcriptional levels of PLK and PNPO had no apparent change. In the day-1 5th instar larvae treated with JHA, the transcriptional levels of PLK and PNPO had no change ; in the day-3 5th instar larvae treated with JHA, however, the transcriptional level of PLK decreased compared with the control at 48 h after treatment （ P 〈 0.05 ）, and the transcriptional level of PNPO decreased compared with the control at 24 and 48 h after treatment （P 〈0.01 ）. In the day-5 5th instar larvae treated with JHA for 24 and 48 h, respectively, the transcriptional levels of PLK and PNPO significantly decreased compared with the control （P 〈 0. 01 ）. [ Conclusion ] The transcriptional expression of PLK and PNPO is influenced by 20-E and JHA, 20-E promotes them in the early stage of the 5th instar larvae while JHA represses them in late stages of the 5th instar larvae. These results lay the foundation for further research on hormone regulation of VB6.