Non-stringent tissue-source requirements for BMP ligand expression in regulation of body size in Caenorhabditis elegans

    loading  Checking for direct PDF access through Ovid

Abstract

Summary

In Caenorhabditis elegans, the Bone Morphogenetic Protein (BMP)-related ligand Dpp- and BMP-like-1 (DBL-1) regulates body size by promoting the larval and adult growth of the large epidermal syncytium hyp7 without affecting cell division. This system provides an excellent model for dissecting the growth-promoting activities of BMP ligands, since in this context the growth and differentiation functions of DBL-1 are naturally uncoupled. dbl-1 is expressed primarily in neurons and the DBL-1 ligand signals to its receptors and Smad signal transducers in the target tissue of the epidermis. The requirements constraining the source(s) of DBL-1, however, have not previously been investigated. We show here that dbl-1 expression requirements are strikingly relaxed. Expression in non-overlapping subsets of the endogenous expression pattern, as well as ectopic expression, can provide sufficient levels of activity for rescue of the small body size of dbl-1 mutants. By analysing dbl-1 expression levels in transgenic strains with different degrees of rescue, we corroborate the model that DBL-1 is a dose-dependent regulator of growth. We conclude that, for body size regulation, the site of expression of dbl-1 is less important than the level of expression.

Related Topics

    loading  Loading Related Articles