0000000001192657
AUTHOR
S. Castagnetti
Spatially restricted expression of PlOtp, a Paracentrotus lividus Orthopedia-related homeobox gene, is correlated with oral ectodermal patterning and skeletal morphogenesis in late-cleavage sea urchin embryos
ABSTRACT Several homeobox genes are expressed in the sea urchin embryo but their roles in development have yet to be elucidated. Of particular interest are homologues of homeobox genes that in mouse and Drosophila are involved in patterning the developing central nervous system (CNS). Here, we report the cloning of an orthopedia (Otp)-related gene from Paracentrotus lividus, PlOtp. Otp is a single copy zygotic gene that presents a unique and highly restricted expression pattern. Transcripts were first detected at the mid-gastrula stage in two pairs of oral ectoderm cells located in a ventrolateral position, overlying primary mesenchyme cell (PMC) clusters. Increases in both transcript abund…
Homeobox genes and sea urchin development.
We describe the expression of three Paracentrotus lividus homeobox-containing genes of the dispersed class during sea urchin embryogenesis and discuss their possible roles in the mechanisms of cell specification and embryo morphogenesis. PIHbox12 represents the first regulator identified in sea urchin that belongs to the zygotic class of transcription factors. Its early and transient expression and the localization of transcripts suggests that PIHbox12 is involved in cell fate specification of the oral or aboral ectodermal territories at the early cleavage stages. PIHbox9 is expressed just after the completion of gastrulation in a narrow stripe of cells at the ectoderm-endoderm boundary. It…