CDNA CLONING AND ESCHERICHIA-COLI EXPRESSION OF UK114 TUMOR-ANTIGEN

Experimental evidence indicates that the antineoplastic effects of UK1 01, a goat liver perchloric acid extract, is likely due to one of its constituent proteins: the 14 kDa protein named UK114. The cDNA encodin g UK114, obtained by PCR methodologies, contains an open reading frame coding for a protein of 137 amino acids with a theoretical molecular mass of 14 298 Da. It shows high sequence homology with a 14 kDa prote in identified in human, rat and Mus musculus tissues which is likely i nvolved in the inhibition of cell-free protein synthesis. Northern blo t analysis indicated that the transcript is present in variable amount s in a wide range of human tissues. Genomic Southern blots revealed th at the UK114 mRNA in goat as well as in human is encoded by a single g ene, as is the case in rat. The expression system for UK114 was constr ucted under the control of the PL promoter from bacteriophage a and th e cDNA coding region has been highly expressed in Escherichia coli as a thioredoxin fusion protein. The recombinant UK114, purified to homog eneity, is immunoreactive to rabbit antisera prepared against UK101 or native UK114, as well as to sera of UK101-treated cancer patients. It inhibits cell-free protein synthesis at 8 mu M concentration. (C) 199 8 Elsevier Science B.V. All rights reserved.