Transgenic analysis of the medaka mesp-b enhancer in somitogenesis.
Somitogenesis is a critical step during the formation of metameric structures in vertebrates. Recent studies in mouse, chick, zebrafish and Xenopus have revealed that several factors, such as T-box genes, Notch/Delta, Wnt, retinoic acid and FGF signaling, are involved in the specification of nascent somites. By interacting with these pathways, the Mesp2-like bHLH transcription factors are transiently expressed in the anterior presomitic mesoderm and play a crucial role in somite formation. The regulatory mechanisms of Mesp2 and its related genes during somitogenesis have been studied in mouse and Xenopus. However, the precise mechanism that regulates the transcriptional activity of Mesp2 has yet to be determined. In our current report, we identify the essential enhancer element of medaka mesp-b, an orthologue of mouse Mesp2, using transgenic techniques and embryo manipulation. Our results demonstrate that a region of approximately 2.8 kb, upstream of the mesp-b gene, is responsible for both the initiation and anterior localization of mesp-b transcription within a somite primordium. Furthermore, putative motifs for both T-box transcription factors and Notch/Delta signaling are present in this enhancer region and are essential for activity.
Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Harumi
H
Terasaki
Ryohei
R
Murakami
Yukuto
Y
Yasuhiko
Tadasu
T
Shin-I
Yuji
Y
Kohara
Yumiko
Y
Saga
Hiroyuki
H
Takeda
D000595:Amino Acid Sequence; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics* / Q000302:isolation & purification; D001665:Binding Sites; D004742:Enhancer Elements, Genetic / Q000235:genetics / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D018014:Gene Transfer Techniques; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009990:Oryzias / Q000196:embryology / Q000235:genetics*; D051880:Receptors, Notch / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D019170:Somites / Q000502:physiology*; D019076:Transgenes / Q000235:genetics*; D014212:Tretinoin / Q000378:metabolism; D015027:Zebrafish
D051792:Basic Helix-Loop-Helix Proteins; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D051880:Receptors, Notch; D014212:Tretinoin; C064045:delta protein