All echinoderm larvae possess a nervous system consisting of a ciliary band and associated sensory ganglia(apical, oral and lateral ganglia) that controls swimming and feeding. Neurons of the larval nervous systemfirst appear as neuroblasts in the thickened ectoderm of the animal plate (anterior neuroectoderm, ANE) atthe late blastula – early gastrula stage and then also in the ciliary band. The neural differentiation process ofsea urchin embryos has been analysed and the Gene Regulatory Network involved in the differentiationprocesses is extensively studied. We have previously isolated an alpha tubulin family member of the seaurchin Paracentrotus lividus (Pl-Tuba1a, formerly known as Pl-Talpha2) that is specifically expressed in theneurogenic territory of embryo (1). In order to identify cis-regulatory elements controlling its spatiotemporalexpression, we conducted gene transfer experiments, transgene deletions and site specificmutagenesis. Thus, a genomic region of about 2.6 Kb of Pl-Tuba1a, containing four InterspecificallyConserved Regions (ICRs), was identified as responsible for proper gene expression. An enhancer role wasascribed to ICR1 and ICR2, while ICR3 exerted a pivotal role in basal expression, restricting Tuba1aexpression to the neurogenic territory of the embryo. The functional analysis of the ICR3 showed that 10 bp(corresponding to a putative forkhead box consensus sequence binding site) are necessary for the geneactivation. Additionally, the point mutation of this site in ICR3 prevents Pl-Tuba1a expression.
|Number of pages||1|
|Publication status||Published - 2016|