Analysis of methylation profile in mitochondrial genome of Exopalaemon carinicauda in response to starvation

As the “energy factory”,the mitochondria play an important role in the metabolism of cells.However,it is little known whether or not the mitochondria in shrimps mediate the energy metabolism-related gene expressions by methylating the motochondrial genome DNA sequences.In this study,in oder to analyze the methylation profile of the mitochondria in response to starvation in the ridgetail white prawn Exopalaemon carinicauda,we designed 51 BSP(bisulfite sequencing PCR)primer pairs where PCR amplification zones covered the whole mitonchondial genome.Of the 51 primer pairs,10 primer pairs could get the predicted PCR products,but only 5 primer pairs were selected for further studies because of their repeatable PCR amplification merits.The methylation profile of different individuals at 10 d,20 d and 30 d after starvation stress were analyzed,using the above 5 primer pairs.Our results showed that the average death time of tolerating starvation for the E.carinicauda was 19.8 days,and the longest tolerating time was 48 days.The DNA methylation in mitochondria genome was found at each starvation stress stage.But,to our surprize,the methylation ratio decreased following the elongation of starvation time.The individuals with DNA methylation were the highest on 10^th d,second on 20^th d,and the least on 30^th d.The DNA methylation was mainly found in the ND genes(NADH dehydrogenase gene)whose expression production was responsible for maintaining the respiratory electron-transport chain in mitochondria.So,we speculated that the funciton of methylation is to control the energy transfer in mitochondia.