TRANSCRIPTOME  ANALYSIS DURING THE METAMORPHOSIS OF THE ASCIDIAN CIONA INTESTINALIS
Tunicates, including ascidians, are recognized as the true “sister group” of vertebrates and are emerging as models to study the development and degeneration of central nervous system (CNS). Ascidian larvae have the typical chordate body plan that includes a dorsal neural tube. During their metamorphosis, a deep tissue reorganization takes place, with some tissues that degenerate while others develop to become functional during the adult life. The larval CNS also degenerates and most neurons disappear, making room to the formation of adult CNS. The genome of the ascidian Ciona intestinalis has been sequenced and annotated, with several CNS specific genes that have been characterized, revealing specification mechanisms shared with humans. These features make ascidian metamorphosis a good model to study the mechanisms underlying physiological CNS degeneration and to compare them to the pathological condition typical of neurodegenerative diseases. In order to shed light on the molecular determinants of C. intestinalis metamorphosis and neurodegeneration, we analyzed its transcriptome at three stages of development: swimming larva (SwL, Hotta stage 28), settled larva (SetL, Hotta stage 32) and metamorphosing larva (MetL, Hotta stage 34). Supported by SoE-SEED-2020 Grant, University of Milan.