Organization and expression of mouse nm23-M1 gene. Comparison with nm23-M2expression

Nm23 is a gene family encoding different isoforms of the nucleotide diphosp hate kinase (NDPK), an enzyme involved in the synthesis of nucleoside triph osphates. In the present study, the organization and expression of the nm23-M1 gene e ncoding the mouse NDPKA isoform are described. This gene is about 10 kb lon g and composed of five exons. The organization and the exon-intron boundari es are strictly conserved as compared to the human and rat related genes. T he gene promoter region did not exhibit any consensus TATA box, SP1 binding element or Inr sequence. By contrast, TCF-1/LEF-1 binding elements and Pit -1 consensus sequence were present. Northern blotting and in situ hybridization methods were carried out in adu lt and 18.5 days post-coitum (dpc) mouse embryo, respectively. They showed tissue-specific expression of nm23-M1 transcripts, despite housekeeping gen e promoter features. The strongest signals were detected in the nervous sys tem, sensory organs and embryonic thymus. In contrast nm23-M2 mRNA was show n to be more widely expressed. The relationship between nm23-M1 gene tissue-specific expression and the pu tative binding element of the promoter region is discussed. (C) 1999 Elsevi er Science B.V. All rights reserved.