[Analysis of the structure of chicken Foxp3 and its expression profile in tissues]

In this study, we cloned the complete coding sequence (CDS) of chicken foxp3 (chfoxp3) gene, analyzed its structure, and investigated its expression profile in different chicken tissues. To be specific, chfoxp3 was cloned from the splenic tissue of 50-day-old specific-pathogen-free chickens, and analyzed by using online bioinformatics tools or software. The expression profiles of the chfoxp3 gene in different chicken tissues were detected by quantitative real-time PCR (qRT-PCR). The results indicated that the chfoxp3 gene contains an 882-bp open reading frame, encoding 293 amino acids hydrophilic protein with a molecular weight of 33.44 kDa. The chFoxp3 protein has a forkhead domain and carries a nuclear localization signal, which is typical in the Fox transcription factor family. The secondary structure of chFoxp3 consists of α-helix (29.35%), extended chain (10.92%), β-turn (5.12%) and random coil (54.61%). The expression of chfoxp3 varied in different tissues. The expression levels of chfoxp3 in chicken heart and pancreas were higher than in spleen, bursa of Fabricius, thymus, and other immune organs (P < 0.01), which was quite different from that of mammals. Phylogenetic tree analysis showed that chFoxp3 belonged to the same clade as other wild birds did, but was far different from that of mammals. These results may facilitate further research on the role of chFoxp3 in immune regulation.