以绵羊MHC区段BAC克隆酶切片段为探针杂交筛选绵羊混合组织cDNA文库

Screening of tissues pooled cDNA library using probes by restricted fragments of BAC positive clones of ovine MHC

在已知中国美利奴羊MHC(Major histocompatibility complex)区段BAC(Bacterial artificial chromosome)克隆序列信息和预测的基因注释前提下,用位于中国美利奴羊基因组BAC文库MHC区段的6个BAC克隆酶切片段为探针,以噬菌斑原位杂交筛选法筛选中国美利奴羊混合组织cDNA文库(库库杂交),对分离到的cDNA阳性克隆进行全序列测定,并与相应的已知序列信息和基因注释的BAC克隆比对以及在NCBI Blastn数据库中序列相似性检索,旨在验证基因注释结果的准确性和对基因(序列)功能的初步分析。实验中,经过两轮杂交共筛选出27个cDNA阳性克隆(序列),并发现这些序列均可定位到相应的BAC克隆上,且25条序列处在注释基因的外显子部分;在NCBI数据库中经Blastn序列相似性检索发现,23条序列与牛基因的序列相似性最高,且与免疫功能密切相关。

Under the premise what we have known bacterial artificial chromosome（BAC）clone sequence information and gene annotation predicted in the Chinese Merino sheep major histocompatibility complex （MHC） region, the digested fragments from 6 BAC clones that were located in the MHC region of the Chinese Merino sheep genome BAC library, which were used to screen the eDNA library using plaque in situ hybridization as probes. The full length of positive eDNA clones （sequences） isolated were completely sequenced, and the sequences obtained were aligned with the corresponding known sequence information and the BAC clones with gene annotation. Meanwhile, the sequence similarity was searched in NCBI Blastn database. This work aimed at verification of accuracy of the gene annotation results and initial analysis of gene （sequence） function. At last, 27 positive eDNA clones （sequences） in total were screened through two runs of hybridi- zation. It was also found that these sequences could be positioned in the corresponding BAC clones, and 25 sequences were located in exon area of the annotated gene. It was verified that 23 sequences had the highest sequence similarity with those in the Bos taurus by searching against the NCBI Blastn database; moreover, the function of these sequences were closely relate to immunology.