Host-related DNA sequences are localized in the body of schistosome adults

Abstract

SUMMARYThe localization of host (mouse)-related DNA sequences in the adults and cercariae ofSchistosoma japonicumandS. mansoniwas examined byin situhybridization using32P-labelled probes. The hybridization signals to the sequences of the mouse type C and type A retroviruses were clearly observed in the subtegumental layer and inner tissues ofS. japonicumadults. In contrast, it was hard to find any signals to these sequences inS. mansoniadults. Distinct signals to theenv-specific region of the mouse ecotropic type C retrovirus were observed in the subtegumental layer and inner tissues ofS. mansoniadults. No signal to the sequence of the mouse type B retrovirus was found on the sections of either schistosome adult. The signals to the sequence of the genomic clone SmM51 derived from maleS. mansoniwere found in the tissues of both the schistosome adults. The signals to the sequences of the mouse type A andenv-specificregion of ecotropic type C retroviruses were not seen in the cercariae of each species, whereas the signals to the sequence of SmM51 were detected inS. mansonicercariae. These observations suggest that host-related DNA sequences might be incorporated unequally into the schistosome genome during development in the final host.