[Cloning and preparation of cDNA probe from BAlb/c mice]

Lactase gene Lac isolated from BALB/c mice was sequenced, in order to clarify the characteristics of its encoding product and prepare the cDNA probe for further researches on Latose Intolerance by in situ experiment.

A total RNA was isolated by Trizol kit from the small intestine of 4wk old BALB/c mice, then its cDNA was obtained by RT-PCR, etc. After sequencing, the cDNA sequence was submitted to NCBI GenBank. Then a prediction of the characteristics of its deduced protein was made by bioinformatics. The The cDNA coding preparation of the cDNA probe was carried out by the method of random primer.

The cDNA coding sequence was possessed of 912 bp, encoding 303 amino acids residues. In the secondary structure of its deduced product, there existed a motif of glycosyl-hydro-F1-1 located between the amino acid residues 121-129, and there was a transmembrane helicers at the C-terminal.

The Lac gene thus obtained is lactase gene authentically; its deduced protein product is lactase.