title: Characterisation and expression of the Fasciola gigantica cathepsin L gene.
abstract: The gene structure of a cathepsin L from Fasciola gigantica was characterised. The gene spans approximately 2.0 kb and comprises four exons and three introns and is a compact gene as in the cases of crustaceous and platyhelminth cathepsins L. Southern blot analysis suggested that a few copies of the genes are sparsely organised in the genome. Of the three intron insertion positions, two of which are in the same position as in the mammalian cathepsin L gene. Phylogenetic analysis revealed that F. gigantica cathepsin L forms a clade with those from Fasciola hepatica, but not with those from Spirometra erinacei and schistosomes. Putative TATA-boxes were found upstream of a transcription initiation site. The sequence analysis of the 5'-upstream of the transcript revealed that the cathepsin L gene is transcribed by cis-splicing fashion. Furthermore, the experiments using recombinant F. gigantica procathepsin L showed that it was processed to an enzymatically active cathepsin L by pH-dependent autocatalysis. However, the pro-peptide deleted cathepsin L showed no enzyme activity, indicating that the pro-region of F. gigantica procathepsin L is essential for the folding and/or refolding of functional cathepsin L. These results are consistent with the observations in mammalian cathepsin L and papain.
authors.affiliation: Department of Parasitology, Central Laboratory of Medical Sciences, Juntendo University School of Medicine, Tokyo 113-0033, Japan. hyamasak@asahikawa-med.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamasaki
authors.forename: Reiko
authors.initials: R
authors.lastname: Mineki
authors.forename: Kimie
authors.initials: K
authors.lastname: Murayama
authors.forename: Akira
authors.initials: A
authors.lastname: Ito
authors.forename: Takashi
authors.initials: T
authors.lastname: Aoki
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D056668:Cathepsin L; D002403:Cathepsins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D003546:Cysteine Endopeptidases; D004591:Electrophoresis, Polyacrylamide Gel; D005209:Fasciola / Q000235:genetics*; D005786:Gene Expression Regulation; D017238:Genes, Helminth / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011499:Protein Processing, Post-Translational; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: D011993:Recombinant Fusion Proteins; D002403:Cathepsins; D003546:Cysteine Endopeptidases; C534281:CTSL protein, human; D056668:Cathepsin L