关键词: 鱼腥草, UGT75C1, 克隆, 原核表达

Abstract:

To clone the anthocyanidin 3-O-glucoside 5-O-glucosyltransferase（UGT75C1） gene from
Houttuynia cordata and analyse the prokaryotic expression. The cloning primers were designed based on
the transcriptome dataset of H. cordata，one unique sequence encoding UGT75C1 was discovered. The
sequence of UGT75C1 was cloned from H. cordata by RT-PCR. The physical and chemical properties，
secondary structure and three-dimensional structure of the UGT75C1 protein were forecasted and
analyzed，and its structure and function were predicted. And the different expression levels of UGT75C1
gene in rhizome，stems，leaves，and flowers of Houttuynia cordata were analyzed by fluorescent
quantitative PCR. And then the cloned opening reading frame of UGT75C1 gene was inserted into vectorpGEX4T-1. The recombinant plasmid pGEX4T- UGT75C1 was expressed in a prokaryotic expression
system after they were transformed into E. coli BL21（DE3）. The fusion proteins were analyzed by
SDS-PAGE. The cDNA contains a 1 461bp open reading frame and encodes a predicted protein of 486
amino acids. Transmembrane regions and no signal peptide were presented in UGT75C1. The PSPG motif
domain of glycosyltransferases was presented in UGT75C1. Relative real-time PCR analysis indicated that
UGT75C1 showed the highest transcript abundance in the leaves，moderate level in the stems and
rhizomes，and the lowest level in the flowers. The UGT75C1 gene was expressed in a prokaryotic
expression system. This study cloned the UGT75C1 gene from H. cordata for the first time. It will provide
a foundation for studying the function of the UGT75C1，and it provide a scientific basis for functional
genomics research of H. cordata and mechanism research of flavonoids biosynthesis.

Key words: Houttuynia cordata, anthocyanidin 3-O-glucoside 5-O-glucosyltransferase, clone, prokaryotic expression