Molecular cloning, expression, and chromosomal localization of a ubiquitously expressed human 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase gene (PFKFB3)

We report the identification of a human 6-phosphofructo-2-kinase/fnrctose 2 ,6-bisphosphatase gene (PFKFB3) isolated from a human fetal brain cDNA libr ary. The gene was localized to 10p15-->p14 by fluorescence in situ hybridiz ation. The entire cDNA (4,322 bp) codes for a polypeptide of 520 amino acid residues (molecular weight, 59.571 kDa). Structural analysis showed the pr esence of a kinase domain located at the amino terminus and a bisphosphatas e domain at the carboxy terminus, characteristic of previously described 6- phosphofructo-2-kinase/fructose 2,6-bisphosphatase isozymes. In addition, a phosphorylation site for cAMP-dependent protein kinase was found at the ca rboxy terminus. Northern blot analysis showed the presence of a unique 4.8- kb mRNA expressed in the different tissues studied. In mammalian COS-I cell s, this cDNA drives the expression of an active isozyme. Taken together, th ese results identify the presence of a gene coding for a human 6-phosphofru cto-2-kinase/fructose 2,6-bisphosphatase isozyme which is ubiquitously expr essed.