Calcium–calmodulin dependent protein kinase I from Macrobrachium nipponense: cDNA cloning and involvement in molting

• The periodic fluctuation in expression of MnCaMKI during the molt cycle.
• The induced expression of MnCaMKI after eyestalk ablation.
• MnCaMKI and MnEcR were significantly decreased in dsMnCaMKI prawns.
• Emotion modulates activity in the ‘what’ but not ‘where’ auditory pathway.
• ‘What’ regions of auditory cortex integrate features of both location and emotion.

Calcium–calmodulin dependent protein kinase I is a component of a calmodulin-dependent protein kinase cascade and involved in many physiological processes. The full-length cDNA of calcium–calmodulin dependent protein kinase I (MnCaMKI) was cloned from the freshwater prawn Macrobrachium nipponense and its expression pattern during the molt cycle and after eyestalk ablation is described. The full-length cDNA of MnCaMKI is 3262 bp in length and has an open reading frame (ORF) of 1038 bp, encoding a 345 amino acid protein. The expression of MnCaMKI in three examined tissues was upregulated in the premolt stage of the molt cycle. Its expression was induced after eyestalk ablation (ESA): the highest expression level was reached 1 day after ESA in hepatopancreas, and 3 days after ESA in muscle. By dsRNA-mediated RNA interference assay, expression of MnCaMKI and ecydone receptor gene (MnEcR) was significantly decreased in prawns treated by injection of dsMnCaMKI, while expression of these two genes was also significantly decreased in prawns treated by injection of dsMnEcR, demonstrating a close correlation between the expression of these two genes. These results suggest that CaMKI in M. nipponense is involved in molting.