1990 Fiscal Year Final Research Report Summary
Studies on Murine Retrovirus-Related Sequences in the Schistosome. DNA
| Project/Area Number |
63480149
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
寄生虫学(含医用動物学）
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| Research Institution | University of Tsukuba |
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Principal Investigator |
IRIE Yuji Univ. of Tsukuba, Inst. Basic Med. Sci., Associate Prof., 基礎医学系, 助教授 (80110485)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Manami Univ. of Tsukuba, Inst. Basic Med. Sci., Assist. Prof., 基礎医学系, 講師 (80188341)
IWAMURA Yukio Univ. of Tsukuba, Inst. Basic Med. Sci., Associate prof., 基礎医学系, 助教授 (90110486)
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| Project Period (FY) |
1988 – 1990
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| Keywords | Schistosomes / DNA / Retrovirus-related sequence / Southern blot / Western blot / ABC method / PCR method |
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| Research Abstract |
Southern hybriaizdtion of the DNA extracted from adults of Schistosoma japonicum and S. mansoni demonstrated the presence of sequences homologous to the env gene of mouse ecotropic and xenotropic retroviruses. DNA sequences homologous to the gag and pol regions of the ecotropic murine leukemia virus, and to the mouse intracisternal A particle and endogenous type C retrovirus were also detected in the DNA of S. japonicum adults and S. mansoni eggs.
Antibodies against the retrovirus envelope glycoprotein (gp70) of mouse xenotropic retrovirus, BALB virus 2 (Bv2) reacted with the adult worms of S. japonicum and S. mansoni. This reaction was completely inhibited after adsorption of the antibodies with virions of retrovirus. The reactive schistosome antigen was located in the subsegumental layer of adult male fluke and in the vitelline gland of the adult female of S. japonicum and S. Bmasoni. Proteins extracted from both parasites were examined by immunoblot analysis. Anti-Bv2 gp70 antiserem
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reacted with those proteins from both schistosomes and the band patterns were different among sexes and species.
Hybridization with a clone SmE15 DNA from S. Bmasoni miracidia as a probe showed no signal in the DNAs from S. Bmansoni adults, indicating these sequences deleted in adults. Hybridization experiments using the probes SmF25 and SmM51 which are 1.3 and 2.2kb fragments cloned from s. mansoni adult females and males respectively, demonstrated no signal to DNA from S. mansoni miracidia. These data suggested the existence of stagespecific DNA sequences in S. mansoni.
Repetitive sequences in the host genome such as mouse type l Alu sequence (Bl), mouse type 2 Alu sequence (B2) and mo-2 sequence, a mouse minisatellite, were detected in the DNAs from adults and eggs of S. japonicum and dggs of S. mansoni. Almost all of the sequences described above were absent in the DNAs of S. mansoni adults. The DNA fingerprints of schistosomes, using the mo-2 sequence, were indistinguishable from each other and resembled those of their murine hosts. Morever, the mo-2 sequence was hypermethylated in the DNAs of schistosomes and its amount was variable in them. These facts indicate that host-related sequence are actually present in schistosomes and that the mo-2 repetitive sequence exists probably in extra-chromosome.
Polymerase chain reaction using the primer sets of gag region of retrovirus revealed the amplification of gag -related sequences in the DNAs of S. japonicum male adults and S. mansoni eggs. Less
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