Transcription regulatory networks in Caenorhabditis elegans

aqp-7 encodes an aquaglyceroporin whose expression in Xenopus oocytes increases either water or glycerol permeability five- to seven-fold; AQP-7 has no function in mass RNAi assays, perhaps reflecting genetic redundancy with its several paralogs; AQP-7 is expressed in muscle punctae (perhaps focal adhesions).

ard-1 encodes a homolog of mammalian 3-hydroxyacyl-CoA dehydrogenase (HADH II)/amyloid-beta binding alcohol dehydrogenase (ABAD) that is predicted to be mitochondrial.

arx-2 encodes the C. elegans ortholog of the Arp2 subunit of the actin-related protein (Arp)2/3 complex.

asg-2 encodes a homolog of subunit G of the membrane-bound F0 proton channel portion of ATP synthase (mitochondrial respiratory chain [MRC] complex V); asg-2 activity is required for growth at a normally high rate and for normal osmoregulation; in addition, asg-2 activity is required for response to hermaphrodite contact, the first step in a series of stereotypical male mating behaviors; an ASG-2::GFP fusion localizes to mitochondria and to cilia of the male-specific CEM neurons.

asm-1 encodes a protein similar to human acid sphingomyelinase (ASM) or sphingomyelin phosphodiesterase; the ASM-1 protein has a putative secretory signal peptide at the N-terminus, saposin-like and proline-rich domains and putative N-linked glycosylation sites; asm-1 shows phosphodiesterase activity when expressed in COS-7 cells; while mammalian ASM is detected as both intracellular and secreted forms, asm-1 was detected exclusively in the secreted form; northern blot analysis indicates that asm-1 is expressed at higher levels in the embryo compared with other stages.

asp-1 encodes a homolog of cathepsin D aspartic protease; it is transcribed exclusively in intestinal cells of the late embryo and early larvae and is not observed in older larvae or adults; ASP-1 is dispensable for neuronal degeneration.

asp-3 encodes an aspartyl protease homolog that is required, in parallel with ASP-4 but downstream of CLP-1 and TRA-3, for degenerative (necrotic-like) cell death in neurons induced by mutations such as mec-4(d), deg-3(d), or gsa-1(gf).

ast-1 encodes a novel ETS-box transcription factor; AST-1 is required for the proper navigation of some interneuron axons to their targets, for differentiation of the ventral cord pioneer neuron AVG, and for pharyngeal morphogenesis; AST-1 is transiently expressed in many head neurons late in their differentiation and axon outgrowth, and in a few pharyngeal cells; AST-1 is at first nuclear, but then relocates to spots in cell bodies and even neuronal processes; hypomorphic ast-1 mutants have axons extending laterally, and crossing over from the right axon tract to the left axon bundle; null ast-1(hd92) mutants are inviable, failing to attach a working pharynx to their cuticle during development and then starving as L1 larvae; behaviorally, hypomorphic ast-1 animals are at least superficially normal, indicating that the ventral nerve cord can tolerate at least some miswiring; AST-1 regulates odr-2 expression, while ast-1 expression is itself regulated by lin-11.