title: Progressive mRNA decay establishes an mkp3 expression gradient in the chick limb bud.
abstract: The apical ectodermal ridge (AER) controls limb outgrowth and patterning, such that its removal causes changes in mesodermal gene expression, cell death and limb truncation. Fibroblast growth factor (FGF) family members are expressed in the AER and can rescue limb bud outgrowth after AER removal. Cells localized underneath the AER are maintained in an undifferentiated state by the FGFs produced by the AER. MAPK phosphatase 3 (mkp3) is a downstream effector of FGF8 signalling during limb bud development and is expressed in the distal limb mesenchyme. The present work evidences a gradient of mkp3 transcripts along the chick limb bud, in a distal to proximal direction. mkp3 transcription occurs only in the most distal limb bud cells and its mRNA gradient throughout the limb results from progressive mRNA decay. We show that FGF8-soaked beads induce ectopic mkp3 expression, indicating that AER-derived FGF8 protein may activate mkp3 in the distal mesenchyme.
authors.affiliation: Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, 4710-057 Braga, Portugal.
authors.forename: Susana
authors.initials: S
authors.lastname: Pascoal
authors.forename: Raquel P
authors.initials: RP
authors.lastname: Andrade
authors.forename: Fernanda
authors.initials: F
authors.lastname: Bajanca
authors.forename: Isabel
authors.initials: I
authors.lastname: Palmeirim
mesh_terms: D000818:Animals; D002642:Chick Embryo; D005091:Exons / Q000235:genetics; D051524:Fibroblast Growth Factor 8 / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018878:Limb Buds / Q000196:embryology / Q000378:metabolism*; D017027:Protein Tyrosine Phosphatases / Q000235:genetics*; D020871:RNA Stability / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D012333:RNA, Messenger; D051524:Fibroblast Growth Factor 8; D017027:Protein Tyrosine Phosphatases