哈白猪甘露聚糖结合凝集素-A基因的遗传特征分析

Genetic characteristics analysis of MBL-A from Harbin white pig

甘露聚糖结合凝集素作为机体重要的天然免疫因子，在机体的抗感染免疫中发挥第一线的作用。其在动物或者禽类血清中水平的高低代表着机体的抗病性，因此可以作为抗病育种的筛选指标之一。研究依据GenBank上发表的甘露聚糖结合凝集素-A的保守序列，设计合成1对引物，采用RT—PCR和TA克隆方法获得重组目的产物，经酶切、PCR扩增和测序鉴定为哈白猪的甘露聚糖结合凝集素-A序列。同源性比较结果表明：哈白猪的甘露聚糖结合凝集素-A与约克夏猪的核苷酸和氨基酸序列同源性最高，为99％；二者核苷酸有3个不同，但是氨基酸有1个差异，位于131位α螺旋颈区内；哈白猪的甘露聚糖结合凝集素-A与人类甘露聚糖结合凝集素-A的氨基酸同源性为60％，而与其他灵长类的氨基酸序列同源性在77％～81％之间，这些数据提示哈白猪的甘露聚糖结合凝集素-A的保守程度相对较高。

Mannan binding lectin（MBL） is an important innate immunity factor which carries out first - host anti - infection function in animals and people. The levels of MBL in serum stand for the ability of disease resistance, so it can be one of indexes during screening disease resistance breeding. In the study, according to the conserved DNA sequence of MBL - A from GenBank, a pair of primers was designed and synthesized. RT - PCR and TA cloning methods were used and recombinant products were acquired, pMBL - A sequence of Harbin white pig was identified by enzyme digestion, PCR technique and sequencing. Sequence analysis indicated that there are the most highest homology between Harbin white pig and Yorkshire pig at nucleotide and amino acid levels, namely 99% ;there are only three different nucleotides between them, but only one amino acid different,the amino acid is suit for positionl31 in α - helix neck. Compared with human being, there is 60% homology at amino acid level, but with other primates, there are 77% - 81% homology, these data proved that pMBL -A from Harbin white pig has higher conserved sequence. In all together, the paper will provide basis for the study of MBL function, screen disease resistance breeding,at the same time it perhaps provide theory data for applying pMBL - A as xenotransplantation organ to cure patient MBL deficient in the future.