Abstract：Escherichia coli F18 (E. coli F18) is the major pathogen causing porcine edema disease (ED) and porcine post-weaning diarrhea (PWD), which leads to tremendous damage and loss to the pig (Sus scrofa) industry all around the world. Previous study pointed that glycosphingolipid biosynthesis-globo series pathway and alpha (1,2) fucose transferase 1 (FUT1) as one of 7 key glycosyl transferase genes of pathway might play an important regulatory role to anti E. coli F18 in piglets. Therefore, given the importance of gene promoter in the regulation of gene transcription, the aim of this study was to identify the transcription initiation site and promoter of FUT1 gene by using bioinformatics to mine the RNA-seq results which obtained early. Besides, we analyzed the promoter CpG islands of FUT1 through online software. Then, dual luciferase reporter gene technology and AliBaba software were used for the analysis of promoter CpG islands and prediction of putative transcription factor binding sites (TFBS), respectively. By comparing the gene sequences of human (Homo sapiens) and porcine information from GenBank database, we found that FUT1 transcription initiation region had 5 kinds of alternative splicing (AS-1, AS-2, AS-3, AS-4 and AS-5) and 2 promoter regions named as promoter 1 and promoter 2. Further research by dual luciferase reporter gene technology detected the transcriptional activity of the 2 promoters. The result showed that transcriptional activity of promoter 2 was extremely significantly higher than that of the promoter 1 (P＜0.01) and the activity of the promoter 2 was 2.75 times of the promoter 1, which illustrated that promoter 2 played leading role in the transcription process. Then, analyzing the CpG island showed that FUT1 promoter 1 contained a CpG island within 500 bp length and promoter 2 with 2 CpG island. Using Alibaba version 2, we analyzed the identified CpG island, and found 20 TFBSs in the FUT1 gene, and specificity protein 1 (Sp1) located in many TFBS region, which might play important roles in the regulation of FUT1. All the results provide a deeper insight into the methylation detection and regulatory mechanism of FUT1 gene in piglets.
