Cloning and characterization of human cathepsin L promoter

Cathepsin L is a lysosomal cysteine protease, which is over-expressed and s ecreted by malignant cells. It is very potent in degrading collagen, elasti n, laminin and other components of the basement membrane and, therefore, ha s been implicated in tumor invasion and metastasis. The structural portion of the human cathepsin L (hCATL) gene was cloned to elucidate its genomic o rganization (Chauhan et al., J. Biol. Chem. 218 (1993) 1039). In the presen t study, a 1.90 kb DNA fragment, containing 1825 bp of the 5' upstream regi on of hCATL and 75 bases of the first exon of the hCATL, was amplified by P CR from an adaptor ligated placental genomic library. This fragment has bee n demonstrated to exhibit promoter activity by luciferase reporter assays. Sequence analysis of this fragment revealed the presence of approximately 2 9 different putative transcription factor binding sites. Several of them li ke AP-4, GATA-1, Lmo2, CEBPB, MZF-1, NFAT, etc. were present more than once in this region. However, a consensus CAAT box but no consensus TATA box wa s found within the 1.0 kb upstream of exon 1. The transcription initiation site of hCATL, using placental total RNA, was mapped to a single adenine re sidue 289 bases upstream of the ATG codon. (C) 2001 Elsevier Science B.V. A ll rights reserved.