title: Inductive interactions regulating body patterning in planarian, revealed by analysis of expression of novel gene scarf.
abstract: Subtractive hybridization was used to search for the early difference in gene expression between anteriorly and posteriorly regenerating tissues of the same region of the planarian body. A sequence (named scarf) specific for posteriorly regenerating tissue was isolated, encoding a soluble C-type lectin consisting of two slightly different carbohydrate-recognition domains. Such an unusual bivalent structure allows attribution of the protein to a novel subfamily of C-type lectins. scarf expression in intact planarian is rather abundant and follows a characteristic pattern not linked to any known morphological structure. We performed a series of experiments using scarf as a molecular marker. Its expression was monitored during different types of regeneration by whole-mount in situ hybridization and reverse-transcription polymerase chain reaction. The obtained data suggest that scarf expression is positively regulated by anterior tissues closely adjacent to the scarf-expressing region, so that their surgical removal results in rapid scarf switch-off. In turn, tissues expressing scarf seem to inhibit its activation anteriorly. This indicates that at least some of the body patterning events in planarians are based on a system of reciprocal inductive interactions rather than on a global morphogen gradient.
authors.affiliation: Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.
authors.forename: E
authors.initials: E
authors.lastname: Bogdanova
authors.forename: M
authors.initials: M
authors.lastname: Matz
authors.forename: V
authors.initials: V
authors.lastname: Tarabykin
authors.forename: N
authors.initials: N
authors.lastname: Usman
authors.forename: D
authors.initials: D
authors.lastname: Shagin
authors.forename: A
authors.initials: A
authors.lastname: Zaraisky
authors.forename: S
authors.initials: S
authors.lastname: Lukyanov
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D019521:Body Patterning / Q000235:genetics*; D015801:Helminth Proteins / Q000235:genetics / Q000502:physiology*; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D010932:Planarians / Q000196:embryology* / Q000235:genetics; D012038:Regeneration / Q000235:genetics
chemical_list: D015801:Helminth Proteins; C111231:scarf protein, Dugesia tigrina