鸡II型干扰素存在亚型

A New Subtype of Interferon-γ Gene Isolated from Huiyang Chicken

采用 RT- PCR法从惠阳胡须鸡克隆了 II型干扰素基因 ( Ch IFNγ2 )。Ch IFNγ2是含 1 9个氨基酸的信号肽和 1 45个氨基酸的成熟蛋白 ,与已报道的鸡 II型干扰素基因( Ch IFNγ)长度一致 ,核苷酸和氨基酸同源性分别为 97%和 92 .7% ;有 1 2处氨基酸发生点变异。 Ch IFNγ2与禽类 IFNγ和哺乳动物IFNγ在氨基酸水平上同源性分别为 6 2 .2 %～ 92 .7%和 2 6 .5 %～ 31 .8%。 1 980年国际干扰素命名委员会建议 ,在一特定的干扰素型别内 ,氨基酸序列或组成方面有差异时可确定为亚型。根据这些规定 ,惠阳胡须鸡Ch IFNγ2可被定为一种新亚型的鸡 II型干扰素。即

IFNγ gene was cloned from total RNA derived from spleen T cells of HY chicken by reverse transcription polymerase chain reaction (RT PCR). The cloned gene, designated ChIFNγ2, was analyzed by sequencing and homology comparing.The result shows that ChIFNγ2 consists of a signal peptide of 19 amino acids and a mature protein of 145 amino acids. ChIFNγ2 is the same in length and shares 97% and 92.7% identities in nucleotide and amino acids respectively with ChIFNγ got from GenBank. The amino acids of ChIFNγ2 with 12 site mutations share 62.7%~92.7% and only 26.6%~31.8% identities with birds and mammals, respectively.Based on the rule of Interferon Nomenclatural committee new subtypes IFNs could be determined by divergences of amino acids. Thus ChIFNγ2 is classified as a new subtype of ChIFNγ. This is the first report that type II IFN has subtype in vertebrate.