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Title: Small gene family encoding an eggshell (chorion) protein of the human parasite Schistosoma mansoni

Abstract

The authors isolated six independent genomic clones encoding schistosome chorion or eggshell proteins from a Schistosoma mansoni genomic library. A linkage map of five of the clones spanning 35 kilobase pairs (kbp) of the S. mansoni genome was constructed. The region contained two eggshell protein genes closely linked, separated by 7.5 kbp of intergenic DNA. The two genes of the cluster were arranged in the same orientation, that is, they were transcribed from the same strand. The sixth clone probably represents a third copy of the eggshell gene that is not contained within the 35-kbp region. The 5- end of the mRNA transcribed from these genes was defined by primer extension directly off the RNA. The ATCAT cap site sequence was homologous to a silkmoth chorion PuTCATT cap site sequence, where Pu indicates any purine. DNA sequence analysis showed that there were no introns in these genes. The DNA sequences of the three genes were very homologous to each other and to a cDNA clone, pSMf61-46, differing only in three or four nucleotices. A multiple TATA box was located at positions -23 to -31, and a CAAAT sequence was located at -52 upstream of the eggshell transcription unit. Comparison ofmore » sequences in regions further upstream with silkmoth and Drosophila sequences revealed very short elements that were shared. One such element, TCACGT, recently shown to be an essential cis-regulatory element for silkmoth chorion gene promoter function, was found at a similar position in all three organisms.« less

Authors:
; ;
Publication Date:
Research Org.:
Departments of Microbiology, State Univ. of New York at Buffalo, Buffalo, NY (US)
OSTI Identifier:
7040431
Resource Type:
Journal Article
Resource Relation:
Journal Name: Mol. Cell. Biol.; (United States); Journal Volume: 8:8
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; DROSOPHILA; GENETIC MAPPING; SCHISTOSOMA; SILKWORM; DNA SEQUENCING; DNA-CLONING; PROTEINS; TRANSCRIPTION; ANIMALS; ARTHROPODS; CLONING; DIPTERA; FLIES; FRUIT FLIES; HELMINTHS; INSECTS; INVERTEBRATES; LEPIDOPTERA; MAPPING; MOTHS; ORGANIC COMPOUNDS; PLATYHELMINTHS; STRUCTURAL CHEMICAL ANALYSIS; TREMATODES; 550200* - Biochemistry; 550400 - Genetics

Citation Formats

Bobek, L.A., Rekosh, D.M., and Lo Verde, P.T.. Small gene family encoding an eggshell (chorion) protein of the human parasite Schistosoma mansoni. United States: N. p., 1988. Web. doi:10.1128/MCB.8.8.3008.
Bobek, L.A., Rekosh, D.M., & Lo Verde, P.T.. Small gene family encoding an eggshell (chorion) protein of the human parasite Schistosoma mansoni. United States. doi:10.1128/MCB.8.8.3008.
Bobek, L.A., Rekosh, D.M., and Lo Verde, P.T.. 1988. "Small gene family encoding an eggshell (chorion) protein of the human parasite Schistosoma mansoni". United States. doi:10.1128/MCB.8.8.3008.
@article{osti_7040431,
title = {Small gene family encoding an eggshell (chorion) protein of the human parasite Schistosoma mansoni},
author = {Bobek, L.A. and Rekosh, D.M. and Lo Verde, P.T.},
abstractNote = {The authors isolated six independent genomic clones encoding schistosome chorion or eggshell proteins from a Schistosoma mansoni genomic library. A linkage map of five of the clones spanning 35 kilobase pairs (kbp) of the S. mansoni genome was constructed. The region contained two eggshell protein genes closely linked, separated by 7.5 kbp of intergenic DNA. The two genes of the cluster were arranged in the same orientation, that is, they were transcribed from the same strand. The sixth clone probably represents a third copy of the eggshell gene that is not contained within the 35-kbp region. The 5- end of the mRNA transcribed from these genes was defined by primer extension directly off the RNA. The ATCAT cap site sequence was homologous to a silkmoth chorion PuTCATT cap site sequence, where Pu indicates any purine. DNA sequence analysis showed that there were no introns in these genes. The DNA sequences of the three genes were very homologous to each other and to a cDNA clone, pSMf61-46, differing only in three or four nucleotices. A multiple TATA box was located at positions -23 to -31, and a CAAAT sequence was located at -52 upstream of the eggshell transcription unit. Comparison of sequences in regions further upstream with silkmoth and Drosophila sequences revealed very short elements that were shared. One such element, TCACGT, recently shown to be an essential cis-regulatory element for silkmoth chorion gene promoter function, was found at a similar position in all three organisms.},
doi = {10.1128/MCB.8.8.3008},
journal = {Mol. Cell. Biol.; (United States)},
number = ,
volume = 8:8,
place = {United States},
year = 1988,
month = 8
}
  • The authors have isolated a series of human liver cDNA clones encoding glutamate dehydrogenase. The cDNA-derived protein sequence specifies a single 558-amino acid long polypeptide including a cleavable signal sequence of 53 amino acids. Blotting analysis of RNA from human, monkey, and rabbit showed that glutamate dehydrogenase mRNA is present in various amounts in all tissues tested. Glutamate dehydrogenase mRNAs are of four sizes and are found in different ratios in different tissues; the predominant ones are {approx} 3.5 and {approx} 2.9 kilobases. Blot hybridization of human genomic DNA to nonoverlapping cDNA fragments revealed multiple bands, many of which hybridizemore » with two or more probes in a manner inconsistent with the existence of a single GLUD gene. Moreover, two separate 36-base synthetic oligonucleotides corresponding to the coding region hybridize to multiple genomic fragments, confirming the existence of more than one GLUD-related gene in human.« less
  • Mechanically transformed schistosomula of Schistosoma mansoni were irradiated with levels of 60Co irradiation between 2.5 and 54 krad, cryopreserved by the two-step addition of ethanediol and rapid cooling technique, and were injected intramuscularly into groups of mice which were perfused 40 days later. The schistosomula were either irradiated and then cryopreserved (IC) or cryopreserved and then irradiated in the frozen state (CI). Development into adult worms was prevented with 4 krad for IC schistosomula, but for CI schistosomula a small number of worms (1.6%) was recovered using 8.8 krad. A dose of 4 krad was sufficient to prevent development ofmore » unfrozen controls (I), but for schistosomula irradiated while exposed to ethanediol (EI), a dose of 7 krad was required. Using the different protocols, the peak levels of protection against a challenge infection were achieved with 9 (IC) and 16 krad (CI), compared to 20 krad for unfrozen schistosomula (I) reported previously. The highest level of protection (65%) was achieved with CI schistosomula. Possible interactions between the radioprotective and damaging effects of cryopreservation are discussed.« less
  • Investigations were undertaken to ascertain: what host organs are reached by Schistosoma cercariae gamma irradiated at different dose levels; the nature and extent of lesions produced in these host organs; and possible similarities existing between the tissue reactions to irradiated cercariae and those observed previously in natural and acquired resistance. Cercariae were exposed to 2500, 5000, and 50,000 rep doses of Co/sup 60/ gamma radiation and immediately injected into mice, the tissues of which were examined for schistosomula 50 days later. Irradiation interfered with the ability of schistosomes to reach maturity in mice. Since the death and disintegration of schistosomulamore » stimulated a considerable degree of inflammation, different dosage levels provided contrasting tissue reactions. At 50,000 rep, cercarial dermatitis wvith ulceration and marked vasculitis was the main pathologic feature; at 5000 rep numerous granulonnatous foci were seen in the lung; and at 2500 rep foci of liver cell necrosis and liver granulomata occurred. Irradiation of 2500 rep appeared to be the best dose since the less heavy concentration of parasites in a single organ produced the least amount of objectionable pathologic changes. The findings confirm that the life span, maturation, and migration of irradiated cercariae are affected in proportion to the irradiation level. No eggs were produced at any of the radiation levels studied. Stunted young adults developed from cercariae irradiated at 2500 rep. These attained their greatest number 40 days after exposure, but by day 50 most of the schistosomula had died, leaving small granulomas and calcified foci as a residue. When cercariae were exposed at 5000 rep, only a few sporadic stunted worms were found in the liver, and with 50,000 rep, most of the schistosomula died in the skin injection site. However, variations of biological vigor were such that even at 50,000 rep some parasites were able to migrate from the skin to the lungs and reach the liver, as shown by onc granuloma observed in that organ. (BBB)« less
  • The ability of cercariae of Schistosoma mansoni to degrade a model extracellular connective tissue matrix produced by rat vascular smooth muscle cells in culture was investigated. In this model, connective tissue macromolecules are present in the interactive framework that characterizes their structure in vivo. Cercariae were stimulated to degrade the matrix by skin lipid or linoleic acid. At the maximally stimulating concentration of linoleic acid (25 ..mu..g/cm/sup 2/), 68% of the total matrix was degraded, including 57% of the glycoprotein, 79% of the elastin, and 8% of the collagen. Degradation of matrix was inhibited by ..cap alpha../sub 1/-proteinase inhibitor andmore » soybean trypsin inhibitor. Ethylenediaminetetraacetic acid inhibited degradation by unstimulated but not linoleic acid-stimulated cercariae. Preacetabular gland secretions collected from cercariae also degraded the matrix with an activity 86% of that of live cercariae. Preacetabular gland proteolytic activity was also inhibited by ..cap alpha../sub 1/-proteinase inhibitor, soybean trypsin inhibitor, and ethylenediaminetetraacetic acid. The similar characteristics of matrix degradation by both live cercariae and cercarial preacetabular gland secretions support the idea that a proteinase secreted from cercarial preacetabular glands facilitates invasion of skin and connective tissue by these larvae. Degradation of elastin and glycoprotein constituentes of extracellular matrix is probably essential for skin penetration.« less
  • Spleen cells of mice vaccinated with radiation-attenuated Schistosoma mansoni cercariae were used to produce monoclonal antibodies directed against newly transformed schistosomular surface antigens. One of these monoclonal antibodies recognized a polypeptide of 18 kDa. Binding was measured by radioimmunoassay. This glycoprotein was purified by monoclonal antibody immunoaffinity chromatography and a polyclonal antiserum was prepared against it. Immunofluorescence assays showed that the polyclonal antiserum bound to the surface of newly transformed schistosomula and lung-stage organisms but not to the surface of liver-stage and adult worms. Using this polyclonal antiserum we isolated recombinant clones from an adult worm cDNA expression library constructedmore » in lambdagt11. Clone 654.2 contained an insert of 0.52 kilobase and hybridized to a 1.2-kilobase mRNA species from adult worms. Most importantly, clone 654.2 produced a fusion protein of 125 kDa that was reactive with sera of vaccinated mice that are capable of transferring resistance. This result encourages future vaccination trials with the fusion protein.« less