Cloning And Expression Analysis Of The Bovine Peptide Transporter I

It has been widely accepted that small peptide was an important absorptive form of dietary protein other than free amino acids. In fact, small peptide-bound amino acid (PBAA) was the only effective form to supply certain amino acids to fulfill the metabolism needs of some starved or sick animals when these amino acids could not be absorbed in free form. Various evidences demonstrated that PBAA and free amino acid (FAA) were absorbed through different transportation systems. Compared with the transportation of FAA, the transportation of PBAA was quicker, energy saving, and uneasy to be saturated. Two types of PBAA transporters have been extensively studied. PepT1 is the transporter mainly found in gastrointestinal tracts and PepT2 was the transporter mainly found in kidney. The nucleotide sequences of the PepT1 of rabbit(2.7kb,Fei et.,1994;Boll et.,1994),human(2.2kb,Liang et.,1995), rat (2.9- 3.0kb,Saito et.,1995), and ovine(2.8kb,Pan,2001)have been successfully cloned and analyzed, while the sequence of bovine PepT1 remains unknown.A primer was designed according to the nucleotide sequence of human, rat, rabbit, and ovine PepT1 publicated in the present study. Parts of the bovine PepT1 sequenced was cloned, amplified, and sequenced. The cloned sequence was latterly used to measure the expression level of BPepT1 in different parts of the gastrointestinal tract of bovine by the real time RT-PCR method. The results of the present study was:1. The sequence of oPepT1 cDNA has been publicated in the GenBank (accession number DQ309694). The length of the sequence was 1566bp, which is the sequence between the third and the tenth structural domain. And it is 82.89%, 80.01%, 78.93%, 96.04%, 83.08%, 63.90%, 85.66% nucleotide...