title: Pax 2 expression in mesodermal segmentation and its relationship with EphA4 and Lunatic-fringe during chicken somitogenesis.
abstract: In the Pax gene family, which encodes DNA-binding proteins, Pax 2 has been known to play important roles in the formation of the midbrain/hindbrain boundary, eye, inner ear and kidney in vertebrates (Bioessays 19 (1997) 755). In this article, we report a segmentally regulated pattern of Pax 2 expression during chicken somitogenesis. Pax 2 mRNA is localized in the rostral end of the unsegmented presomitic mesoderm (PSM), abutting anteriorly on a prospective segmentation border. This pattern repeats every segmentation cycle (90 min) observed in ovo and also in the half embryo culture assay in which one half of PSM along the midline is fixed immediately while the other half is cultured for a given period. We also determined the sequence of changes in Pax 2 expression during a segmentation cycle by comparing the pattern of Pax 2 with that of Lunatic-fringe (L-fringe), known to cycle periodically in posterior PSM. A systematic comparison of the expression patterns between Pax 2, L-fringe and EphA4 further highlighted a close relationship between EphA4 and Pax 2 during a segmentation cycle. Lastly, Pax 2 is not segmentally expressed in mouse PSM, suggestive of species (avian)-specific mechanisms underlying somitic segmentation.
authors.affiliation: Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara 630-0101, Japan.
authors.forename: Rinako
authors.initials: R
authors.lastname: Suetsugu
authors.forename: Yuki
authors.initials: Y
authors.lastname: Sato
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Takahashi
mesh_terms: D000818:Animals; D030161:Avian Proteins; D002642:Chick Embryo; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D016695:Glycosyltransferases / Q000378:metabolism*; D008648:Mesoderm / Q000378:metabolism*; D051379:Mice / Q000196:embryology; D051762:PAX2 Transcription Factor; D036122:Receptor, EphA4 / Q000378:metabolism*; D019170:Somites / Q000378:metabolism; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism
chemical_list: D030161:Avian Proteins; D004268:DNA-Binding Proteins; D051762:PAX2 Transcription Factor; C497319:Pax2 protein, mouse; D014157:Transcription Factors; D016695:Glycosyltransferases; C498394:LFNG protein, Gallus gallus; C498392:Lfng protein, mouse; D036122:Receptor, EphA4