Receptor tyrosine phosphatase psi is required for Delta/Notch signalling and cyclic gene expression in the presomitic mesoderm.
Segmentation in vertebrate embryos is controlled by a biochemical oscillator ('segmentation clock') intrinsic to the cells in the unsegmented presomitic mesoderm, and is manifested in cyclic transcription of genes involved in establishing somite polarity and boundaries. We show that the receptor protein tyrosine phosphatase psi (RPTPpsi) gene is essential for normal functioning of the somitogenesis clock in zebrafish. We show that reduction of RPTPpsi activity using morpholino antisense oligonucleotides results in severe disruption of the segmental pattern of the embryo, and loss of cyclic gene expression in the presomitic mesoderm. Analysis of cyclic genes in RPTPpsi morphant embryos indicates an important requirement for RPTPpsi in the control of the somitogenesis clock upstream of or in parallel with Delta/Notch signalling. Impairing RPTPpsi activity also interferes with convergent extension during gastrulation. We discuss this dual requirement for RPTPpsi in terms of potential functions in Notch and Wnt signalling.
Aerne
Birgit
B
Developmental Genetics Laboratory, Cancer Research UK, 44 Lincoln's Inn Fields, London WC2A 3PX, UK.
Ish-Horowicz
David
D
D000818:Animals; D001483:Base Sequence; D002642:Chick Embryo; D003001:Cloning, Molecular; D018507:Gene Expression Regulation, Developmental; D015723:Gene Library; D017403:In Situ Hybridization; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins / Q000378:metabolism*; D008648:Mesoderm / Q000378:metabolism*; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense / Q000737:chemistry; D009991:Oscillometry; D014176:Protein Biosynthesis; D017434:Protein Structure, Tertiary; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism / Q000502:physiology*; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2; D051880:Receptors, Notch; D015398:Signal Transduction; D014158:Transcription, Genetic; D015027:Zebrafish
D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D016376:Oligonucleotides, Antisense; D051880:Receptors, Notch; C064045:delta protein; D017027:Protein Tyrosine Phosphatases; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2