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Updated: Aug 13, 2026

Simultaneous Assessment of Cardiomyocyte DNA Synthesis and Ploidy: A Method to Assist Quantification of Cardiomyocyte Regeneration and Turnover
Published on: May 23, 2016
Calcyclin binding protein promotes DNA synthesis and differentiation in rat neonatal cardiomyocytes
Ka-Wing Au1, Cecy Y C Kou, Anthony Y H Woo
1Department of Biochemistry and Croucher Laboratory for Human Genomics, The Chinese University of Hong Kong, Shatin, NT, China.
Abstract:
During cardiac muscle development, most cardiomyocytes permanently withdraw from the cell cycle. Previously, by suppressive subtractive hybridization, we identified calcyclin-binding protein/Siah-interacting protein (CacyBP/SIP) as one of the candidates being upregulated in the hyperplastic to hypertrophic switch, suggesting an important role of CacyBP/SIP in cardiac development. To show the importance of CacyBP/SIP during myoblast differentiation, we report here that CacyBP/SIP is developmentally regulated in postnatal rat hearts. The overexpression of CacyBP/SIP promotes the differentiation and DNA synthesis of H9C2 cells and primary rat cardiomyocytes, as well as downregulates the expression of beta-catenin. Besides, CacyBP/SIP promotes the formation of myotubes and multinucleation upon differentiation. To investigate the cardioprotective role of CacyBP/SIP in cardiomyocytes, a hypoxia/reoxygenation model was employed. We found that CacyBP/SIP was upregulated during myocardial infarction (MI) and hypoxia/reoxygenation. As a conclusion, CacyBP/SIP may play a role in cardiomyogenic differentiation and possibly protection of cardiomyocytes during hypoxia/reoxygenation injury.
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