Transcription regulatory networks in Caenorhabditis elegans

ceh-26 encodes a protein that contains a prospero-related homeodomain; expressed in nuclei of the adult head, tail neurons, and one cell in the postdeirids.

ceh-33 encodes a Six/sine oculis class homeodomain transcription factor; preliminary RNAi experiments suggest that CEH-33 activity may be required for gonad development; a ceh-33::gfp reporter shows very weak pharyngeal expression in late embryos and early larvae.

ceh-38 encodes two proteins, by alternative splicing, that belong to the ONECUT class of homeodomain proteins (which includes mammalian hepatocyte nuclear factor-6); ceh-38 is expressed from embryos to adults, and in many different tissues (e.g., pharynx, gut, hypodermis and many nerve cells), but has no known function in vivo.

ceh-40 encodes one of two C. elegans homeodomain proteins homologous to Extradenticle (Exd/Pbx); ceh-40 genetically interacts with ceh-20 and unc-62 during embryonic development: while loss of ceh-40 activity alone results in no significant embryonic lethality, loss of ceh-40 and ceh-20, or ceh-40, ceh-20, and unc-62, results in incompletely penetrant embryonic lethality.

cpg-1 encodes, by alternative splicing, two isoforms of a protein with three chitin-binding peritrophin-A domains and two mucin-like regions; CPG-1 is individually dispensable for normal embryonic development; however, CPG-1 and CPG-2 are jointly required for osmotic integrity of early embryos, error-free chromosomal segregation during meiosis, polar body extrusion, association of the sperm pronucleus/centrosome complex (SPCC) with the early embryonic cortex, localization of PAR-2 in early embryos, posterior localization of P granules or PIE-1, and pseudocleavage; CPG-1, like CPG-2, is covalently linked to chondroitin, which itself is required for vulval morphogenesis, polar-body extrusion, and separation of the eggshell from the embryonic plasma membrane; cpg-1 mRNA, like that of cpg-2, is expressed specifically in the adult hermaphrodite germ line and is bound by GLD-1; CPG-1 has five potential chondroitin attachment sites, one of them verified by mass spectrometry, and transgenic CPG-1 synthesized in mammalian cells carries chondroitin sulfate chains; CPG-1's multiple peritrophin-A domains may enable mechanical cross-linking of chitin.

ces-2 encodes a basic region leucine-zipper (bZIP) transcription factor, most similar in sequence and binding specificity to the PAR (proline- and acid-rich) subfamily of bZIP proteins; ces-2 is required to activate programmed cell death in the sister cells of the serotoninergic neurosecretory motor (NSM) neurons, and is transcriptionally inhibited by activated LET-60(G12V).

cey-2 encodes a cold-shock/Y-box domain-containing protein; by homology, CEY-2 is predicted to function as either an RNA-binding protein involved in translation or RNA processing, or a DNA-binding protein involved in transcriptional regulation; cey-2 mRNA is expressed maternally in the early embryo, in a pattern characteristic of class II maternal RNAs, which are initially detected throughout the embryo but restricted to the P, or germline, lineage as cell division progresses; CEY-2 associates with CGH-1 and CEY-3/4 in cytoplasmic particles of the gonad and early embryo; as loss of cey-2 activity via large-scale RNAi screens does not result in any obvious abnormalities, the precise role of cey-2 in C. elegans development and/or behavior is not yet known.

cey-4 encodes a Y box-containing protein with no known function in vivo; CEY-4 associates with CGH-1 and CEY-2/3 in cytoplasmic particles of the gonad and early embryo.

chd-3 encodes a PHD-finger SNF2 family member containing a chromo domain and a C-terminal helicase domain that affects Notch-dependent vulval development; expressed in virtually all embryonic cells and in many larval nuclei.

che-2 encodes a protein that contains G-protein beta-like WD-40 repeats that affects chemotaxis, dauer formation, and longevity; expressed in the cilia of most ciliated sensory neurons, some head neurons, and male tail rays.