The Effect Of KK-42 On HSP MRNA Of Litopenaeus. Vannamei

Heat shock proteins (HSP) play important roles in coping with environmental stresses and self-protection in animals.. KK-42 is a kind of juvenile hormone antagonist. Our previous study has demonstrated that the treatment of imidazole derivative KK-42 can increase the survival rate of Litopenaeus vannamei In order to research the possible molecular mechanism of KK-42 effect on Litopenaeus vannamei and in view of heat shock protein 70 and heat shock protein 90 are important in biological environment adaptability and self-protection ,the effect of KK-42 on the expressions of hsp90 and hsp70 were determined .The shrimps, 3.5-5.0 cm long, were soaked for 1 min in KK-42 solution at a concentration of 1.95×10^-4 M, and then cultured in normal way. The mandibular organ(Mo), muscle(Mu),hepatopancreas(He) and eyestalk(Es) were collected during the process of cultivation. RNA of those organs and tissue were extracted. The tissue distribution of HSP90 and HSP70 was assayed. In addition, HSP90 in shrimp Litopenaeus vannamei have been clone and analyzed. the spatial and temporal expressions of hsp90 and hsp70 as well as the effect of KK-42 on the expressions were determined .The heat shock protein 90(HSP90) gene, was cloned from hepatopancreas of Litopenaeus vannamei by 3'and 5'rapid amplification of cDNA ends (RACE) PCR. The full-length HSP90 cDNA consists of 2543 bp with a 105 bp 5'-UTR,a 278 bp 3 '-UTR and a 2160 bp open reading frame, encoding 720 amino acids. The molecular mass of the deduced amino acid is 82.8 KDa with an estimated pI of 6.65. Sequence comparison showed that HSP 90 of Litopenaeus vannamei shares 97.80%, 97.22% identity with that of Fenneropenaeus chinensis and Metapenaeus ensis.The transcripts of HSP90 gene and HSP70 gene were detected in all tissue tested. In the experiment,hsp90 and hsp70 mRNA levels in hepatopancreas were higher than in other organs . Real-time PCR analysis indicated that HSP90 and HSP70 showed different expression profiles in shrimp hepatopancreas after treatment. Compared to treatment group, hepatopancreas HSP90 and HSP70 mRNA levels were relatively lower although the obvious fluctuations of the levels were found during experiment in control group. Administration of KK-42 could significantly induce hepatopancreas hsp90 and hsp70 expressions. The HSP70 and HSP90 mRNA contents increased by 243.4%, 141.3%, 410.5% and 121.6%, 505.5%, 481.7%, respectively, compared with the corresponding controls on day 1, day 2 and day 3 after KK-42 treatment.Our present study demonstrates that KK-42 treatment significantly induces the transcriptions of hsp90 and hsp70 from hepatopancreas, which is likely one of the mechanisms of promoting-survival effect of KK-42 on Litopenaeus.vannamei.