Functional Research Of Fus On Body Growth And Development Of Zebrafish

With the developing of biological basic research,the function exploration of genes has always been one of the important topics in life science research.It not only has important theoretical significance in understanding the phenomena of biological development,but also affects the application of production practices.The Fused in sarcoma gene?FUS?is a RNA-binding protein implicated in the regulation of transcription and pre-mRNA splicing.According to previous research reports,mutations in FUS lead to neurodegenerative diseases including ALS?amyotrophic lateral sclerosis?in mammals.However,little is known about fus function in fish species.In our study,we used the zebrafish?Danio rerio?as a model organism to explore the function of the fus gene in fish.The zebrafish fus is located on chromosome 3 and consists of 14059 bases.The cDNA is 1626 bp in length and encodes a total of 541 amino acids.Its coding sequence contains two domains of the RRM superfamily and Zinc finger domain add Zinc finger domain in Ran-binding proteins?ZnF_-RBZ?.Based on the functional domain of this gene,we selected suitable target sites on the genome as close as possible to the translation initiation codon,and we generated frame-shift alleles in the zebrafish fus using CRISPR/Cas9 mutagenesis.Homozygous fus mutants were obtained by progeny crossing.The results showed that in both of the larvae and adult in the zebrafish development,the fus^-/-homozygous mutants developed normally and were fully fertile,except that their body size and body weight were smaller than that of the wild type ones?WT?.In addition,the female-biased sexual size dimorphism in adult zebrafish was also eliminated when fus was mutated.Further study of several growth-related genes in growth and development signaling pathways revealed that the expression levels of gh1,ghra,igf1,igf2a,stat5.1 and socs6 were significantly reduced in fus^-/-zebrafish larvae compared with the wild type.However,there was no effect on locomotor activity in fus^-/-zebrafish compared with WT.Our research indicated that different from its functions in mammals,fus is not associated with motoneuron development and has a divergent function in regulating somatic growth and sexual size dimorphism in fish species.