The International Journal of Developmental Biology

Int. J. Dev. Biol. 44: 777 - 784 (2000)

Vol 44, Issue 7

Transcriptional regulation of the gene for epidermal growth factor-like peptides in sea urchin embryos

Published: 1 October 2000

K Yamasu, G Suzuki, K Horii and T Suyemitsu

Department of Regulation Biology, Faculty of Science, Saitama University, Urawa, Japan.


Exogastrula-inducing peptides (EGIPs), which are epidermal growth factor-related peptides of the sea urchin Anthocidaris crassispina, are substances that elicit abnormal gastrulation (exogastrulation) during embryogenesis of the sea urchin. In the present study we have examined the regulation of the expression of the EGIP precursor gene (EGIP) in sea urchin embryos. Whole mount in situ hybridization showed that EGIP is zygotically expressed afterthe onset of gastrulation in subdomains of the embryonic and larval ectoderm. The expression is confined in early gastrulae to small ectodermal regions adjoining the vegetal plate, which progressively expand to almost the entire ectoderm except the oral hood and postoral tips of the arms in later stages. In adults the expression is restricted to the ovary. Zygotic EGIP expression is sensitive to dissociation of embryonic cells, as well as to disruption of the extracellular matrix (ECM) with 5-cis-hydroxyproline, suggesting requirements for interaction with neighboring cells and/or with the ECM. The expression of reporter genes (chloramphenicol acetyl transferase and green fluorescent protein) under the regulation of the 4.6 kb upstream region of EGIP is temporally and spatially similar to that of the endogenous gene, showing that EGIP expression is regulated at the transcription level during embryogenesis by the cis-elements within the 4.6 kb upstream region.

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