Characterization of a fragment containing a putative TLP cDNA sequence.

With the aim of isolating the Tumor Liberated Protein (TLP) gene, reverse transcription-polymerase chain reaction (RT-PCR) was used to isolate a approximately equal to 500 bp fragment containing a putative TLP cDNA sequence. Total RNAs were extracted from several cell lines with RNAzol B reagent (Tel-Test, Inc) and reverse transcribed using the Reverse Transcription System (Promega). PCR was carried out for 35 cycles (1 minute at 95 degrees C, 2 minutes at 40 degrees C and 1 minute at 72 degrees C) using an upstream degenerate oligonucleotide, ACN AAY AAR GAR GCN TCN ATG TG, which corresponds to the amino acid sequence T N K E A S I, and random hexamers as the downstream primer. PCR products were electrophoresed on a 1% agarose gel containing ethidium bromide. The PCR products were cloned in the pGEM-T easy vector (PROMEGA) and the resulting plasmid clones were sequenced with the chain termination method using the Applied Biosystems model 373A DNA sequencer. A putative open reading frame was deducted. The results obtained can be considered as preliminary data that will require more investigation in order to confirm them. We propose to continue the studies to verify that TLP could be a diagnostic marker in human cancer.