中文摘要：

从白桦（Betula platyphylla Suk．）形成层相关组织cDNA文库中获得一个木聚糖内糖基转移酶XET基因全长eDNA序列，其ORF全长882bp，编码由293个氨基酸残基组成的多肽，编码蛋白的分子质量为33．1ku，理论等电点为5．49。运用生物信息学方法对该蛋白进行理化性质分析及保守区预测，确定其属于糖基水解酶16超家族；进一步模拟蛋白空间结构，得到了可靠的分子生物学模型；利用sqRT—PCR分析白桦组培苗不同器官内XET基因的表达情况，结果显示XET在发育中的根茎叶内都有较高的表达水平。

英文摘要：

A full length of xyloglucan endotransglycosylase （XET） gene was cloned from a cDNA library of procambium from Betula platyphylla. The ORF of XET is 882 bp in length, encoding 293 amino acid residues with molecular weight of 33.1 D and theoretical isoelectrlc point of 5.49. The analysis of conserved domains proves that the gene contains conserved sequence of XET protein and belongs to a member of Glycosyl hydrolases family 16. The three-dimensional structure of XET protein was further simulated, and a reliable molecular biology model was obtained. The expression pattern of XET gene in different organs in B. platyphylla was investigated using the semi-quantitative RT-PCR. Results showed that the XET gene was expressed in developing roots, stems and leaves to a similar high level.