Kohji Hotta

The ascidian chordate Ciona intestinalis is an established model organism frequently exploited to examine cellular development and a rapidly emerging model organism with a strong potential for developmental systems biology studies. However, there is no standardized developmental table for this organism. In this study, we made the standard web-based image resource called FABA: Four-dimensional Ascidian Body Atlas including ascidian's three-dimensional (3D) and cross-sectional images through the d

Ciona robusta (Ciona intestinalis type A), a model organism for biological studies, belongs to ascidians, the main class of tunicates, which are the closest relatives of vertebrates. In Ciona, a project on the ontology of both development and anatomy is ongoing for several years. Its goal is to standardize a resource relating each anatomical structure to developmental stages. Today, the ontology is codified until the hatching larva stage. Here, we present its extension throughout the swimming la

Expression of the Brachyury (Ci-Bra) gene of the ascidian Ciona intestinalis is initiated at the 64-cell stage. Gene expression is restricted to notochord precursor cells, and Ci-Bra plays a key role in notochord differentiation. In a previous study, nearly 50 cDNA clones for potential Ci-Bra-downstream genes that are expressed in notochord cells were isolated. The present determination, by whole-mount in situ hybridization, of the temporal expression patterns of 19 notochord-specific and 20 not

In vertebrates, Brachyury, a T-box transcription factor gene, seems to have a dual role in the differentiation of axial midline mesoderm cells into notochord and gastrulation cell movements regulated by non-canonical Wnt/planar cell polarity (Wnt/PCP) signaling. To understand the function of Brachyury-downstream genes in chordate embryos, from a series of our survey on differential expression, including subtractive hybridization, dot-blot assays, EST sequences and the expression patterns in whol

Formation of the chordate body is accomplished by a complex set of morphogenetic movements including convergent extension of notochord cells. In the ascidian Ciona intestinalis, Brachyury plays a key role in the formation of the notochord, and more than 30 Bra-downstream notochord genes have been identified. In the present study, we examined the effects of functional suppression of nine Bra-downstream notochord genes, which include Ci-PTP, Ci-ACL, Ci-prickle, Ci-netrin, Ci-trop, Ci-Noto3, Ci-ASA

Marine invertebrate larvae are known to begin metamorphosis in response to environmentally derived cues. However, little is known about the relationships between the perception of such cues and internal signalling for metamorphosis. To elucidate the mechanism underlying the initiation of metamorphosis in the ascidian, <i>Ciona intestinalis</i> type A (<i>Ciona robusta</i>), we artificially induced ascidian metamorphosis and investigated Ca²⁺ dynamics from pre- to post-metamorphosis. C

Abstract In ascidian Ciona intestinalis , a subset of trunk epidermal neurons were shown to possess external network of neural projections. To characterize a more complete network in naturally hatched (chorionated) larvae, we visualized the structure with a confocal laser scanning microscope. High resolution images revealed the huge network consisting of several subnetworks in whole‐larval tunic. We named this network the ASNET ( as cidian dendritic ne twork in t unic). The ASNET was dynamically