title: A novel Syk-family tyrosine kinase from Schistosoma mansoni which is preferentially transcribed in reproductive organs.
abstract: The complete coding deoxyribonucleic acid for a novel tyrosine kinase (TK) of the human parasite Schistosoma mansoni has been cloned and characterized. The molecule was designated TK4. The sequence predicts a translation product of about 140 kDa containing two Src homology 2 domains and a tyrosine kinase domain. Data base analyses indicate that TK4 belongs to the Syk family of TKs which has not been identified in schistosomes or other Acoelomata yet. The presence of a member of the Syk family in this phylum supports previous findings demonstrating that TK subclasses were established early in evolution. Although Northern blot and reverse transcription polymerase chain reaction analyses show transcription of TK4 in larval stages and adult schistosomes of both genders, TK4 is more abundantly transcribed in males. In situ hybridization data demonstrate the gender-independent occurrence of TK4 transcripts in parenchymatic cells. Significant signals were detected in the oocytes of the female and in the spermatocytes of the male suggesting that TK4, among other functions, may play a role in germ cell development. This is an unexpected finding considering that Syk-family TKs of invertebrates and vertebrates described so far are not involved in the differentiation of the gonads.
authors.affiliation: Institute for Genetics, Genetic Parasitology and Centre for Biological and Medical Research, Heinrich-Heine-Universität, Universitätsstrasse 1, 40225, Düsseldorf, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Knobloch
authors.forename: Ralf
authors.initials: R
authors.lastname: Winnen
authors.forename: Marcus
authors.initials: M
authors.lastname: Quack
authors.forename: Werner
authors.initials: W
authors.lastname: Kunz
authors.forename: Christoph G
authors.initials: CG
authors.lastname: Grevelding
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D005854:Germ Cells / Q000201:enzymology* / Q000378:metabolism; D015801:Helminth Proteins; D017403:In Situ Hybridization; D008297:Male; D008969:Molecular Sequence Data; D009865:Oocytes / Q000201:enzymology / Q000378:metabolism; D010802:Phylogeny; D011505:Protein-Tyrosine Kinases / Q000235:genetics*; D018510:RNA, Helminth / Q000235:genetics / Q000378:metabolism; D012550:Schistosoma mansoni / Q000201:enzymology / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013090:Spermatocytes / Q000201:enzymology / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D018076:DNA, Complementary; D015801:Helminth Proteins; D018510:RNA, Helminth; D011505:Protein-Tyrosine Kinases; C471156:TK4 protein, Schistosoma mansoni