title: Expression of engrailed in the developing brain and appendages of the onychophoran euperipatoides kanangrensis (Reid).
abstract: We have cloned an engrailed-class gene in the onychophoran Euperipatoides kanangrensis and investigated its expression using in situ hybridisation. The expression pattern was found to differ drastically from that previously described for another onychophoran species. In the present investigation, engrailed transcripts were detected in a subset of developing neurons in the brain anlage, and in the mesoderm as well as ectoderm of the developing limb buds. The engrailed positive cells of the brain are of differing developmental maturity, ranging from subepidermal neuronal precursors to neurons located basally in the embryo with developing axons. The lack of the traditional expression in the posterior compartment of segments reported earlier in onychophorans is discussed, and we suggest that onychophorans may have acquired two copies of engrailed with different functions.
authors.affiliation: Department of Earth Sciences, Palaeobiology Programme, Palaeontology Group, Uppsala University, Norbyvägen 22, SE-752 36 Uppsala, Sweden. je271@cam.ac.uk
authors.forename: B Joakim
authors.initials: BJ
authors.lastname: Eriksson
authors.forename: Earl T
authors.initials: ET
authors.lastname: Larson
authors.forename: Per-Ove
authors.initials: PO
authors.lastname: Thörnqvist
authors.forename: Noel N
authors.initials: NN
authors.lastname: Tait
authors.forename: Graham E
authors.initials: GE
authors.lastname: Budd
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D001921:Brain / Q000196:embryology / Q000378:metabolism*; D017931:DNA Primers; D005121:Extremities / Q000196:embryology*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D017403:In Situ Hybridization; D007448:Invertebrates / Q000196:embryology*; D008969:Molecular Sequence Data; D009474:Neurons / Q000378:metabolism; D009517:New South Wales; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D018398:Homeodomain Proteins; D014157:Transcription Factors; C106185:engrailed homeobox proteins