Cloning and bacterial expression of postnatal mouse heart FGF-16.

Fibroblast growth factor-16 (FGF-16) has been reported as the sixteenth member of the heparin sulphate proteoglycan binding growth factor family, which includes acidic and basic FGFs (FGF-1 and FGF-2), based on sequence similarity. The sequences of human (h) and rat (r) FGF-16 complimentary DNA (cDNA) sequences are known. Rat FGF-16 is expressed in brown adipose tissue during embryonic development but also shows some specificity for the postnatal heart. In spite of the importance of other FGF family members in cardiac physiology, there is scant information about FGF-16 function. As a first step towards exploiting mouse genetics in this regard, we have used reverse transcriptase-polymerase chain reaction and primers based on the rFGF-16 sequence to clone the adult mouse (m) FGF-16 cDNA. An mFGF-16 cDNA of 624 base pairs was generated. Based on sequence analysis, mFGF-16 and hFGF-16 share at least 95.2 and 99% nucleotide and amino acid similarity, respectively. In terms of other family members, FGF-16 is most closely related to FGF-9. When used as a radiolabeled probe, the mFGF-16 cDNA detected a single 1.8 kilobase transcript in adult mouse heart RNA. The mFGF-16 cDNA was also used to generate an amino-terminal poly-histidine tagged FGF-16 protein in bacteria. Using sodium dodecyl sulphate-polyacrylamide gel electrophoresis and taking into account the poly-histidine tag, an FGF-16 protein of 26.3 kDa was detected. The generation of cardiac mFGF-16 cDNA and a purified FGF-16 protein preparation are seen as important tools in the further characterization of FGF-16 expression and function in the mammalian heart.