On the connective tissue regulator Follistatin-like 1

Even though for many years the molecular mechanisms underlying cardiac development have been studied, the majority of cardiac defects remain unexplained. Defects in the cardiac connective tissue component result in a large proportion of heart defects such as valve and septal defects. Previous studies suggested a role for the gene Follistatin-like 1 (Fstl1) in the development of the connective tissue component of the heart based on unbiased genome-wide analysess and its expression pattern in the heart.
We studied the role of Fstl1 in the development of the heart, skeletal and tendinous system. By deletion of Fstl1 in these tissues we found that normal expression of Fstl1 is crucial for normal development. In addition we unveiled a novel signalling role for the endocardium-derived tissue in regulating atrio-ventricular conduction velocity by expressing Fstl1. Unfortunately, the role of Fstl1 in the molecular regulation of the development of the heart, skeleton and tendons remained still largely enigmatic and will be subject of future investigations.