New Roles for the Heterochronic Transcription Factor LIN-29 in Cuticle Maintenance and Lipid Metabolism at the Larval-to-Adult Transition in .

Temporal regulation of gene expression is a crucial aspect of metazoan development. In the roundworm , the heterochronic pathway controls multiple developmental events in a time-specific manner. The most downstream effector of this pathway, the zinc-finger transcription factor LIN-29, acts in the last larval stage (L4) to regulate elements of the larval-to-adult switch.

Regulation of C. elegans L4 cuticle collagen genes by the heterochronic protein LIN-29.

The cuticle, the outer covering of the nematode C. elegans, is synthesized five times during the worm's life by the underlying hypodermis. Cuticle collagens, the major cuticle component, are encoded by a large family of col genes and, interestingly, many of these genes express predominantly at a single developmental stage.

Use of an activated beta-catenin to identify Wnt pathway target genes in caenorhabditis elegans, including a subset of collagen genes expressed in late larval development.

The Wnt signaling pathway plays a fundamental role during metazoan development, where it regulates diverse processes, including cell fate specification, cell migration, and stem cell renewal. Activation of the beta-catenin-dependent/canonical Wnt pathway up-regulates expression of Wnt target genes to mediate a cellular response. In the nematode Caenorhabditis elegans, a canonical Wnt signaling pathway regulates several processes during larval development; however, few target genes of this pathway have been identified.