Developmental expression of mouse Follistatin-like 1 (Fstl1):: Dynamic regulation during organogenesis of the kidney and lung

Follistatin-like 1 (Fst11) is a distantly related homolog of the Activin and Bone Morphogenetic Protein antagonist Follistatin. Interestingly, this molecule also has homology with the extracellular matrix modifying protein BM-40/SPARC/osteonectin. Previous studies in chick have identified Fst11 as a regulator of early mesoderm patterning, somitogenesis, myogenesis and neural development. In this study, we determine the developmental expression pattern of Fst11 in the mouse. We find that Fst11 is ubiquitously expressed in the early embryo,, and that expression becomes regionalized later during development. In the majority of tissues, Fst11 is strongly expressed in the mesenchymal component and excluded from the epithelium. Notable exceptions include the central nervous system, in which Fst11 expression is entirely absent with the exception of the choroid plexi and floor plate, the lung, in which Fst11 expression can be seen in airway epithelia and the kidney, in which collecting ducts and nascent nephron epithelia express the highest levels of Fst11. (c) 2006 Elsevier B.V. All rights reserved.