Molecular characteristics and tissue expression analysis of the chicken genes SPOP and MyD88

【Objective】 To describe the molecular characteristics of SPOP and MyD88 genes and their expression in different tissue during chicken development, and lay the basis for the subsequent study of their regulation of tissue growth and development in chickens and the development of disease-resistance breeding.【Method】 The coding regions(CDS) of chicken SPOP and MyD88 genes were cloned by RT-PCR. ExPASy, SOPMA, SWISS-MODEL and PSORT II Prediction were used for bioinformatics analysis. Real-time quantitative PCR(qRT-PCR) technology was used to detect the expression of SPOP and MyD88 genes in various tissues at 14 embryonic days(E14 d) in chick embryos and at 1-day-old(H1 d), 7-day-old(H7 d), and 14-day-old(H14 d) after shelling.【Result】 The CDS sequences of chicken SPOP and MyD88 genes were 1125 and 900 bp, encoding 374 and 299 amino acid residues, respectively. The molecular formula of the SPOP protein was C₁₈₆₆H₂₉₂₆N₄₉₆O₅₅₉S₂₈, and was predicted to have a molecular weight of 42 kD and a isoelectric point(pI) of 5.58. The molecular formula of the MyD88 protein was C₁₅₀₂H₂₃₉₄N₄₁₀O₄₃₈S₁₈ and was predicted to have a molecular weight of 33 kD and a pI of 5.93. Both SPOP and MyD88 were relatively unstable proteins. The chicken SPOP and MyD88 proteins, were mainly located in the cytoplasm(60.9%) and their secondary structures mainly consisted of α -helixes and random loops. Compared with humans and mammals, the three functional domains of chicken SPOP(MATH, BTB-POz and BACK) were conserved, while the two functional domains of MyD88(Death and TIR) had multiple amino acid site variations. SPOP and MyD88 genes were expressed in all tissues of chicken at different developmental stages, but their expression in the lung was relatively the highest. The differences in expression of SPOP and MyD88 was extremely significant(P<0.01, the same below). From E14 d to H14 d, the expression of SPOP gene in the eyeball and lung showed an overall upward trend, but the lung expression of SPOP stabilized before H14 d. The expression of SPOP gene in the brain, heart, stomach muscle and liver showed an upward trend followed by a downward trend. The expression of MyD88 gene in the eyeball, liver and lung was first increased, followed by a decrease and a further increase. The expression of MyD88 gene in stomach and chest muscles decreased and reached the lowest value at H14 d.【Conclusion】 The expression levels of SPOP and MyD88 genes are relatively high in lung, eyeball and stomach muscle of chicken embryo at different developmental stages. The expression levels of SPOP are extremely significantly higher than MyD88 and the relative expression levels of SPOP gene and MyD88 gene are negatively correlated, indicating that SPOP gene regulates the expression of MyD88 gene.