Characterisation of a family of Schistosoma japonicum proteins related to dynein light chains

Dynein light chains (DLC) are components of dynein, an enzyme complex invol ved in various aspects of microtubule-based motility. We report here the mo lecular cloning and sequencing of cDNAs encoding a family of DLC-like polyp eptides (SjcDLC1-5) from the human bloodfluke Schistosoma japonicum with op en reading frames of 87-104 amino acids and deduced molecular masses rangin g from 10.5 to 12.3 kDa. Two-dimensional Western blot analysis confirmed th e presence of several S. japonicum DLC isoforms with differing pi values an d molecular sizes. We also describe the molecular characterisation, genomic organisation and expression of clone SjcDLC1, and the immunological charac terisation and localisation of its encoded protein. Northern blot analysis of adult worm RNA indicated SjcDLC1 is encoded by a single message of appro ximately 650 bp and Southern analysis suggested one SjcDLC1 gene exists in the S. japonicum genome. Immunolocalisation studies demonstrated that the S jcDLC1 protein is present in the tegument of the adult and cercarial stages of S. japonicum. SjcDLC1 and the other SjcDLC may function in the transpor t of specialised organelles, comprising membranous and discoid bodies, thro ugh the tegument to the schistosome-unique heptalaminate tegumental membran e at the external surface of the adult worm. As a consequence, they may pro vide novel targets for anti-schistosome vaccine and/or drug development. (C ) 1999 Elsevier Science B.V. All rights reserved.