Heussler V T, Eichhorn M, Dobbelaere D A
Department of Parasitology, University of Berne, Switzerland.
Gene. 1992 May 15;114(2):273-8. doi: 10.1016/0378-1119(92)90587-f.
A human interleukin 4 (hIL-4)-encoding cDNA (hIL4) probe was used to screen a bovine genomic library, and three clones containing sequences with homology to the human and mouse IL4 cDNAs were isolated. Sequence information obtained from one of these genomic clones was used to design an oligodeoxyribonucleotide primer corresponding to the transcription start point region for use in the polymerase chain reaction (PCR). The PCR-RACE protocol, designed for the rapid amplification of cDNA ends, was successfully used to generate a full-length bovine IL4 (bIL4) cDNA clone from polyadenylated RNA isolated from concanavalin A-stimulated bovine lymph node cells. The bIL4 cDNA is 570 bp in length and contains an open reading frame of 405 nucleotides (nt), coding for a 15.1-kDa precursor of 135 amino acids (aa), which should be reduced to 12.6 kDa for unglycosylated bIL4 after cleavage of a putative hydrophobic leader sequence of 24 aa. The aa sequence contains one possible Asn-linked glycosylation site. Bovine IL4 is shorter than mouse (mIL4) and hIL4, because of a 51-nt deletion in the coding region. Comparison of the overall nt and deduced aa sequences shows a greater homology of bIL4 with hIL4 than with mIL4. This homology is not evenly distributed, however, with the nt sequences 5' and 3' of the coding region showing a much greater homology between all three species than the coding sequence.
使用编码人白细胞介素4（hIL-4）的cDNA（hIL4）探针筛选牛基因组文库，分离出三个与人和小鼠IL4 cDNA具有同源序列的克隆。从其中一个基因组克隆获得的序列信息用于设计与转录起始点区域相对应的寡脱氧核糖核苷酸引物，用于聚合酶链反应（PCR）。为快速扩增cDNA末端而设计的PCR-RACE方案成功用于从伴刀豆球蛋白A刺激的牛淋巴结细胞中分离的聚腺苷酸化RNA生成全长牛IL4（bIL4）cDNA克隆。bIL4 cDNA长度为570 bp，包含一个405个核苷酸（nt）的开放阅读框，编码一个135个氨基酸（aa）的15.1 kDa前体，在切割一个24 aa的推定疏水前导序列后，未糖基化的bIL4应减少到12.6 kDa。氨基酸序列包含一个可能的天冬酰胺连接的糖基化位点。由于编码区有51 nt的缺失，牛IL4比小鼠（mIL4）和人IL4短。整体核苷酸和推导氨基酸序列的比较表明，bIL4与hIL4的同源性高于与mIL4的同源性。然而，这种同源性分布并不均匀，编码区5'和3'的核苷酸序列在所有三个物种之间显示出比编码序列更高的同源性。
