Abstract
Understanding the molecular basis of heart development is an important research area, because malformation of the cardiovascular system is among the most frequent inborn defects. Although recent research has identified molecules responsible for heart morphogenesis in vertebrates, the initial specification of heart progenitors has not been well characterized. Ascidians provide an appropriate experimental system for exploring this specification mechanism, because the lineage for the juvenile heart is well characterized, with B7.5 cells at the 110-cell stage giving rise to embryonic trunk ventral cells (TVCs) or the juvenile heart progenitors. Here, we show that Cs-Mesp, the sole ortholog of vertebrate Mesp genes in the ascidian Ciona savignyi, is specifically and transiently expressed in the embryonic heart progenitor cells (B7.5 cells). Cs-Mesp is essential for the specification of heart precursor cells, in which Nkx, HAND and HAND-like (NoTrlc) genes are expressed. As a result, knockdown of Cs-Mesp with specific morpholino antisense oligonucleotides causes failure of the development of the juvenile heart. Together with previous evidence obtained in mice, the present results suggest that a mechanism for heart specification beginning with Mesp through Nkx and HAND is conserved among chordates.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
