Meeting Abstract
The long and short forms full-length myostatin cDNA (MrMstn) for the fresh water shrimp Macrobrachium rosenbergii had been cloned and characterized. Amino acid sequence analysis revealed that the two cDNAs are identical in the overlapping propeptide region. Sequence alignment and phylogenetic analysis revealed that all myostatins are evolutionary related and their amino acid sequences are highly conserved at the C-terminal end. Results from expression studies indicated that MrMstn is widely expressed in different tissues including the eyestalk, hepatopancreas, muscle, and heart, etc. Furthermore, the expression level of MrMstn in the muscle is the highest in late post-molt stage (stage B). MrMstn could be detected in different life cycle stages including the ovary, early embryo, post-larvae, juveniles, subadult and adults. Additionally, the expression level decreased from early to advanced life stages. RT-PCR cloning of MrMstn from shrimp of different life cycle stages revealed that MrMstn cDNA is highly polymorphic. Different alternatively splicing variants could be identified in different tissues and different life cycle stages. Transcript variants that consist of truncated N-terminal or C-terminal end could be identified as well as deletion of different cDNAs. The synthesis of different alternatively spliced transcripts would increase the proteome diversity and might have a regulatory role in controlling the equilibrium of functional MrMstn in vivo. Although no muscle doubling was observed in the injected shrimp, as reflected from the low transcription rate of the myosin and b-actin, the expression of other genes such as myocyte enhancing factor and follistatin were affected. This study could further enhance our understanding of the role of myostatin in shrimp.
