Molecular cloning of the rat TA1/LAT-1/CD98 light chain gene promoter

The rat LAT-1 (L-amino acid transporter-1) gene is a CD98 light chain highl y expressed in cancer and development. As an initial study of the molecular basis underlying regulation of its expression, we cloned 2 kb of the LAT-1 5' flanking region. Inverse RACE and primer extension methods were used to define the transcription initiation site at 80 bp upstream from the transl ational start site. Functional studies carried out in normal hepatic cells using constructs containing progressive 5' deletion from region -1958 to -1 85 showed 3-5-fold P-galactosidase activities over control. The presence of an activator site(s) between -52 and -185 was indicated by low activities conferred by the construct spanning this region. (C) 2001 Elsevier Science B.V. All rights reserved.