Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0909432107 (2010)

A developing heart, at least in zebrafish, needs electrical conduction to grow into a functional organ.

Neil Chi at the University of California, San Diego, Didier Stainier at the University of California, San Francisco, and their colleagues focused on a zebrafish mutant (pictured bottom) in which the heart contracts asynchronously and eventually fails. Genetic analysis revealed that the mutated gene is cx46, which codes for a protein that connects adjacent cardiac cells, allowing electrical impulses to move from cell to cell and thus coordinate heart contraction.

Mutant hearts had abnormal conduction and slower transmission of electrical signals than hearts in normal zebrafish (top). The cardiac cells also had deformed shapes. Mice lacking the same gene had similar conduction defects, some of which have been linked to human heart malfunction and failure.

The authors suggest that electrical stimulation may improve the effectiveness of experimental tissue-repair techniques that transplant cells into damaged hearts.

Credit: N. CHI