Transcriptomic and functional analysis as strategies for understanding the determinate and indeterminate muscle growth patterns of fish

Abstract

Muscle growth in fish occurs by mosaic hypertrophy and hyperplasia. Fish with mosaic hyperplasia and stratified throughout life have indeterminate growth, such as Piaractus mesopotamicus (pacu) and fish with mosaic hyperplasia more restricted to the first days after hatching, have determined growth, such as Danio rerio (zebrafish). Numerous studies carried out over the years have contributed to knowledge about muscle growth, however, this process is not fully understood. In this sense, omics analysis are efficient tools that provide a global view of genes that coordinate complex processes, such as muscle growth. Furthermore, the use of omic data from public databases is a strategy that can provide new information about biological networks involved with phenotype control and muscle growth. Thus, this project aims to analyze and compare the transcriptomic profile of the skeletal muscle of P.mesopotamicus (pacu) and D.rerio(zebrafish), juvenile and adult, as well as finding possible markers of growth, maintenance and distinction of these muscle phenotypes. For these purposes, transcriptomic datasets from both adult species will be searched and downloaded from the European Nucleotide Archive (ENA). Concomitantly, we will carry out the sequencing of the skeletal muscle of the same species in the juvenile phase. The same processing pipeline, using specific bioinformatics tools, will be used for the data that will be downloaded and for the data that will be sequenced. Based on these data, the following comparisons will be made: adult pacu x zebrafish; juvenile x adult pacu; juvenile zebrafish x juvenile pacu, juvenile zebrafish x adult zebrafish. Through these comparisons, Differently Expressed Genes (GDEs) will be obtained and used in ontology analysis and for the construction of molecular interaction networks. The Heatmap will be built for the proper interpretation of the generated data and for the selection of target genes between comparisons, which will be validated by RT-qPCR and Western-blotting, in both species. Functional analyzes of in situ hybridization and gene inhibition, through morpholinos, will also be performed from these targets in zebrafish (in vivo) and in pacus (in vitro). Considering the robust methodology that will be used, it is expected that the knowledge generated by this project can contribute to studies involving the area of muscle biology in fish; that it is applied in the elaboration of innovation projects, which are of great interest to the productive sector.