Identification of Tβ4 knock-in goat. A: Tβ4 gene knock-in goat (1704) and controls (1702 and 1703). B: Immunocytochemistry identification of the expression of Tβ4 gene in fibroblasts separated from the WT, 1702, 1703, and1704 goats. C: Quantitative analysis of fluorescence signals by Image pro plus. D: PCR detection by two pairs of primers showed in Fig. 2A and sequenced results of the integration sites. E: Southern blot confirmed site-specific insertion; target fragments combined with probes is 3.6kp. F: Real-time PCR identification of the Tβ4 gene in WT, 1702, 1703 and1704 goats. Error bars represent mean ± SD. * p < 0.05; **p < 0.01.