DIFFERENTIAL SCREENING OF A HUMAN PANCREATIC ADENOCARCINOMA LAMBDA-GT11 EXPRESSION LIBRARY HAS IDENTIFIED INCREASED TRANSCRIPTION OF ELONGATION-FACTOR EF-1-ALPHA IN TUMOR-CELLS

A human pancreatic adenocarcinoma lambda-gt11 expression library was differentially screened with mRNA derived from normal and cancerous pancreatic tissues. Five clones preferentially hybridized with pancreatic adenocarcinoma mRNA. cDNA inserts from 4 of these clones were amplified by PCR, labelled with alpha-P-32 and used in Northern blot analysis against mRNA prepared from a variety of tumour and normal tissues. Lambda-GER-4 identified a pancreas-associated mRNA (> 10 kb) with no homology with known sequences at either the nucleic or amino-acid level. Lambda-GER-2 identified a 1.7-kb mRNA transcript that was over-expressed in mRNA prepared from pancreas, colon, breast, lung and gastric tumours relative to normal tissues. Sequence analysis and restriction-enzyme mapping showed that this clone was completely homologous with the active form of human elongation factor EF-1-alpha. This high level of EF-1-alpha-mRNA expression in tumour tissues lends support to the increasing evidence that EF-1-alpha is an important regulator of the cell cycle.