Figure 1
miR-203 expression is correlated with chicken embryonic skeletal muscle development. (a) miRNA microarray indicates that miR-203 has abundant detection signals in E14 leg muscles of dwarf and normal White Rock Chickens (black bars). However, the signals were very low in 7-wk-old chickens (red bars). E14 represents an embryo at day 14. 7W represents a chick that was 7 weeks of age. (b) Northern blot analysis validated that miR-203 is expressed in E14 leg muscle of dwarf chickens but not in that of the 7-wk-old dwarf chickens. U6 was used as the reference gene. (c) In situ hybridisation of dwarf chicken E14 leg muscles using anti-miR-203 or scramble confirmed the presence of miR-203 in muscle tissue. Dark blue staining shown by arrows indicates miR-203-positive hybridisation signals. (d) The expression of miR-203 is significantly higher in the E14 leg muscle of dwarf chickens than in that of normal chickens. miR-203 relative expression was determined by qPCR. (e) The expression of miR-203 in the leg muscle of embryonic dwarf chickens was determined by qPCR. The ages of the chickens were embryo day 10, embryo day 12, embryo day 14, embryo day 16, embryo day 18 and chick at postnatal 1 day of age. The fold change in miR-203 expression, normalised by U6, is expressed relative to E14 miR-203 expression. The results are expressed as the mean±S.E.M. of three replicates. *P<0.05; **P<0.01; ***P<0.001. (f) Northern blot analysis validation of miR-203 expression in the leg muscle of embryonic dwarf chickens. (g) The E14 leg muscle weight of normal and dwarf female chickens. The E14 leg muscle weight of normal chickens is significantly heavier than that of dwarf chickens. (h) H-E staining of histological sections of representative leg muscle from E14 dwarf and normal chickens (magnification, × 40). (i) The male and female leg muscle weights of dwarf chickens were collected and measured from embryos at different stages. The red dashed line was placed according to the growth trend from E10–E16, and the red arrows represent an inflection point of muscle growth. Muscle weight is increased faster after E16. (j) H-E staining of leg muscle fibre cross section from E10 to 1day in dwarf chickens (magnification, × 40)
