Abstract: To analyze the molecular characteristics, tissue distribution, and dynamic expression patterns post-pathogen infection of Keratin 8（Krt8）gene in zebrafish（Danio rerio）, this study cloned the coding sequence（CDS）of the zebrafish Krt8 and conducted a bioinformatics analysis. The expression distribution of the Krt8 gene in the intestine, liver, kidney, and skin tissues of healthy zebrafish was examined using real-time quantitative PCR, and its spatiotemporal expression pattern following infection with Shewanella algae was analyzed. The results showed that the CDS of the zebrafish Krt8 gene encoded a protein consisting of 520 amino acids with a molecular weight of 57.76 kDa, featuring 14 phosphorylation sites. Phylogenetic tree analysis indicated a close evolutionary relationship between the amino acid sequence of zebrafish Krt8 and that of Sinocyclocheilus anshuiensis. Furthermore, the Krt8 gene was expressed in the intestine, liver, kidney, and skin tissues of zebrafish, with the highest expression level observed in the liver. Following infection with S. algae, differential expression patterns of Krt8 were noted in the tested tissues, with a downregulation in the intestine and an initial increase followed by a decrease in the liver and kidney. In summary, the findings of this study suggest that Krt8 in zebrafish may play a role in the organism's immune response or pathophysiological processes induced by S. algae infection. These insights provide a valuable reference for further investigations into the functional mechanisms and roles of Krt8 protein.

Key words: Keratin 8, zebrafish, bioinformatics analysis, tissue distribution, spatiotemporal expression