Transcription regulatory networks in Caenorhabditis elegans

The bli-1 gene encodes an unusual cuticular collagen that is required for proper strut formation within the unique medial layer of the adult cuticle; bli-1 interacts genetically with other cuticular collagens such as bli-2 and rol-1, and may be processed for secretion by BLI-4, a Kex2/subtilisin serine endoproteinase; consistent with its role in adult cuticle formation, bli-1 mRNA is highly expressed only during the L4 larval stage.

brc-2 encodes a BRC domain-containing protein that is homologous to human BRCA2 which when mutated leads to early-onset breast cancer 2 or hereditary male breast cancer (OMIM:600185); in C. elegans, BRC-2 activity is essential for RAD-51-mediated repair of meiotic and radiation-induced double-strand breaks (DSBs); BRC-2 physically interacts with RAD-51 and single-stranded DNA and is required for proper localization of RAD-51 to sites of DNA damage and stabilization of RAD-51-DNA filaments; BRC-2 can also promote RAD-51-independent DSB repair via single-strand annealing (SSA) when the homologous recombination (HR) and nonhomologous end joining pathways (NHEJ) are compromised; in nonirradiated animals, BRC-2 is seen at diffuse, low levels in germline nuclei, but upon radiation treatment BRC-2 localizes to discrete foci that coincide with presumptive sites of DNA damage.

bre-3 encodes a protein similar to beta-glycosyltransferases from bacteria that is required for the toxicity of Bacillus thuringiensis Cry5B; BRE-3 may act in a pathway with bre-5 and is expressed and functions in the gut epithelium.