DIFFERENTIAL EXPRESSION IN ESCHERICHIA-COLI OF THE ALPHA-FORM AND BETA-FORM OF HEPARIN-BINDING ACIDIC FIBROBLAST GROWTH FACTOR-I - POTENTIAL ROLE OF RNA SECONDARY STRUCTURE

Synthetic DNA fragments encoding the entire open-reading frame of human heparin-binding growth factor-1 (HBGF-1-beta) and its NH2-terminal truncated form (HBGF-1-alpha) were constructed. When both constructs were expressed in Escherichia coli under control of the trp-lac promoter, biologically active HBGF-1-alpha, but not HBGF-1-beta was produced in high yield. However, high level expression of HBGF-1-beta was obtained using the T7 polymerase expression vector. Computer analysis of HBGF-1-beta predicts the potential for the formation of exaggerated RNA secondary structure near the translation initiation codon and this could be implicated in contributing to the poor translation of HBGF-1-beta under the trp-lac promoter.