An investigation into a role for follistatin in early cardiogenesis in Xenopus Laevis

Retinoic acid (RA) plays a crucial role in regulating cardiomyocyte differentiation and heart tube formation, but excess RA inhibits cardiomyocyte differentiation. We have used microarray technology and whole mount in situ hybridization to investigate the mechanism by which RA might alter cardiogenesis. Our results showed that RA inhibits cardiomyocyte differentiation at least partially through increasing follistatin gene expression and decreasing BMP signaling. Using cultured explants of the heart region, we demonstrated that addition of BMP4 and activin rescued the inhibitory effects of follistatin and RA on cardiomyocyte differentiation. These results indicate that the increased follistatin (FS) gene expression, known to decrease BMP signaling, may be responsible for the inhibition of heart development. In order to investigate the role of follistatin in cardiogenesis, we also examined follistatin’s developmental profile. We found that follistatin is expressed in the heartforming region in early heart development, which suggests that follistatin is involved in cardiogenesis. In addition, we first showed that excess RA inhibits Tbx20 gene expression in the heart-forming region. This provides another mechanism by which excess RA inhibits cardiogenesis in addition to the known inhibition of Nkx2.5 expression and BMP signaling.

Name thesis:degree_name

M Sc

Discipline thesis:degree_discipline

Physiology

Year dc:date.issued

2007

Author dc:creator

• Yong, Zhao

Advisors dc:contributor.advisor

• Drysdale, Thomas A
• Beier, Frank
• Leco, Kevin J.

• retinoic acid
• cardiogenesis
• Xenopus
• follistatin
• BMP
• Nkx2.5

Handle dc:identifier.uri

https://hdl.handle.net/20.500.14721/19913

OAI identifier oai:identifier

oai:uwo.scholaris.ca:20.500.14721/19913