[Cloning and sequencing of nm23-H3b, a new gene identified to nm23].

Nm23 is a kind of an effective tumor metastasis suppressor gene which included two types in human: nm23-H1 and nm23-H2. Amino acid identity between nm23-H1 and nm23-H2 was 88%. In this study, we used a pair of primers to flank the part of coding sequence of nm23. The 5'-translated sequence was amplified by PCR from human normal liver genomic DNA. A 375bp clone was characterized to designate pnm 23-H3b. The nm23-H3b nucleotide sequence between 40bp and 70bp was different from nm23-H1 and nm23-H2, and other sequences had 86% and 90% identical to nm23-H1 and nm23-H2, respectively. Southern blot containing Bg1II-digested human liver genomic DNA hybridized to the entire nm23-H3b DNA and showed three bands at 10.5, 7.9 and 4.0 kb. These data demonstrate that nm23-H3b is a new type of gene, which has high homology with human nm23-H1 and nm23-H2. Nm23 is possibly considered a family of closely related genes.