High impact information on egl-5

• Here we show that ham-2 encodes a zinc finger protein that acts downstream of egl-5 to direct HSN cell migration, an early differentiation event [1].
• In an unc-86; ham-2 double mutant the HSNs are defective in EGL-43 down-regulation, an egl-5-like phenotype that is absent in either single mutant [1].
• A subset, the two PLM cells, also express the Hox gene egl-5, an Abdominal-B homolog, which we find is required for correct mec-3 expression in these cells [2].
• The Caenorhabditis elegans spalt-like gene sem-4 restricts touch cell fate by repressing the selector Hox gene egl-5 and the effector gene mec-3 [2].
• Such expression is dependent on the Hox gene mab-5, as it is in branches where egl-5 is normally expressed [3].

Biological context of egl-5

• This gene maps on the third chromosome of C. elegans, at the same locus as egl-5, a gene already known to be essential for the determination of specific neurons [4].
• The Caenorhabditis elegans lin-39, mab-5 and egl-5 Hox genes specify cell fates along the anterior-posterior body axis of the nematode during postembryonic development, but little is known about Hox gene functions during embryogenesis [5].
• Regulated expression of egl-5 in this cell lineage is necessary for development of the sensory rays of the male tail. sop-3 encodes a predicted novel protein of 1475 amino acids without clear homologs in other organisms [3].
• Therefore, egl-5 is required for making a subset of rays capable of adopting dopaminergic identity, while the function of the DBL-1 pathway signal is to pattern the realization of this capability [6].
• Increasing or decreasing the gene dosage of mab-5, an Antennapedia homolog, and egl-5, an Abdominal B homolog, results in displacement and fusion of specific rays [7].

Anatomical context of egl-5

• The affected cells are related only by position and not by ancestry. egl-5 is also required for normal development of the somatic gonad and sex muscles in males [8].
• A major site of egl-5 expression and function is in the epithelium joining the posterior digestive tract with the external epidermis [9].

Regulatory relationships of egl-5

• Thus, sop-3 contributes to the combinatorial control of egl-5 by blocking egl-5 activation by MAB-5 and the Wnt pathway in inappropriate lineage branches [3].

Other interactions of egl-5

• In addition, lin-22 activity prevents two other Hox genes, lin-39 and egl-5, from acquiring new activities within their normal domains of function along the A/P body axis [10].
• For example, neurons are specified along the anterior-posterior body axis through the action of the Hox genes lin-39, mab-5, and egl-5 [11].
• Using the ceh-11 homeobox as a probe, a third homeobox (ceh-13) was isolated from a cDNA library [4].
• Two of them (ceh-11 and ceh-12) were isolated from a genomic library by hybridization at low stringency with the Ascaris lumbricoides homeobox AHB-1 [4].
• We have examined the expression of ceh-7 in mutant backgrounds of egl-5 and also mab-5, an Antp/Ubx/Abd-A homologue [12].

Analytical, diagnostic and therapeutic context of egl-5

• Dissection of cis-regulatory elements in the C. elegans Hox gene egl-5 promoter [13].

References