Abstract: Follistatin (FST) gene of Taihang chicken was analyzed by bioinformatics methods and its expression differences in different tissues and follicles at different developmental stages was explored, and the effect of FST on the laying performance of Taihang chickens was analyzed. Coding region of FST gene was cloned and sequenced for 43-week-old healthy Taihang chicken, functional structure was predicted by bioinformatics softwares. Quantitative PCR (Q-PCR) was used to detect the expression differences of FST gene in different tissues and follicles at different developmental stages of Taihang chickens. Three replicates were set in each group and three parallel experiments were carried out. The results showed that the coding region of FST gene of Taihang chicken was 1 032 bp, encoding 343 amino acids. Homology analysis indicated that FST protein had the highest homology with Gallus gallus (100.0%), and both had Sec signal peptide. The mature protein had two conserved domains: FOLN and KAZAL_FS. Physicochemical properties analysis of FST protein showed that it was hydrophilic protein, whose molecular formula was C₁₆₁₉H₂₅₆₇N₄₅₉O₅₂₀S₄₄, molecular weight was 38.192 6 ku, and theoretical isoelectric point was 5.59, the highest content was Cys (C, 10.50%). The secondary structure consisted of α-helix, extended chain, β-corner and random coil, accounting for 16.33%, 16.62%, 5.25% and 61.81%, respectively. qPCR revealed that FST gene was expressed in all tissues, the highest expression was found in liver. During follicle development, FST gene was expressed highest in the large white follicles (P<0.01), there was a 1.6-fold difference in expression before and after follicle selection. These results provided important basic data for studying FST gene in Taihang chicken, and provided a reference for the further mining candidate gene for egg-laying performance of hens.

Key words: Taihang chickens, follistatin, cloning, expression, bioinformatics