Polycomb group - WD40 domain - a component of the Polycomb repressive complex 2 (PRC2) - in combination withEnhancer of zeste and histone deacetylases, promotes gene silencing - required for proper morphogenesis of sensory neuron dendrites
Gene model reviewed during 5.46
There is only one protein coding transcript and one polypeptide associated with this gene
Component of the Esc/E(z) complex, composed of Caf1-55, esc, E(z), Su(z)12, and possibly pho. The Esc/E(z) complex may also associate with Pcl and Rpd3 during early embryogenesis. This complex is distinct from the PRC1 complex, which contains many other PcG proteins like Pc, Ph, Psc, Su(z)2. The two complexes however cooperate and interact together during the first 3 hours of development to establish PcG silencing. Interacts with corto in vitro.
Click to get a list of regulatory features (enhancers, TFBS, etc.) and gene disruptions (point mutations, indels, etc.) within or overlapping Dmel\esc using the Feature Mapper tool.
esc transcripts as detected by RT-PCR are abundant in 0-3 and 3-6 hour embryos. In the second half of embryonic development, zygotic esc transcripts begin to accumulate but are slow to complete splicing. Overall levels decrease dratically in later embryonic stages and are high again only in adult ovaries.
esc transcripts are uniformly distributed in early embryos with the exception of the pole cells. During germ band extension, they become concentrated in the germ band but are absent from the anterior and dorsal parts of the embryo corresponding to the antennal, pre-antennal, and labral regions. Levels drop off sharply at germ band retraction. Transient expression of esc is observed at stage 13 in the supraesophageal ganglion.
esc protein isdetected in mitotic cells and primary spermatocytes in the testis. Expression is initially diffusely nuclear. However, esc staining progressively accumulates in nuclear foci. Protein levels diminish as spermatocytes mature.
The esc protein which is abundant in unfertilized eggs, is increasingly taken up by the accumulating nuclei during cleavage and syncytial blastoderm stages, and is found in all nuclei of cellular blastoderm embryos. The concentration of uniformly distributed esc protein decreases during gastrulation. During germ band extension and retraction, esc is expressed in a limited number of neuroblasts that occur in a segmentally repeated pattern. Subsequently, this pattern disappears and only a few cells in the brain continue to retain esc protein.
GBrowse - Visual display of RNA-Seq signalsView Dmel\esc in GBrowse 2
Please Note This section lists cDNAs and ESTs that fall within the genomic extent of the gene model, which may include cDNAs and ESTs of genes within introns, or of overlapping genes. Please see GBrowse for alignment of the cDNAs and ESTs to the gene model.
For each fully sequenced cDNA the DGRC maintains various forms of the cDNA (e.g tagged or untagged) in several different host vectors for subsequent cloning and expression in Drosophila and Drosophila cell lines.
esc is required for for the maintenance of dendritic fields in class IV dendrite arborisation (da) neurons.
dsRNA has been made from templates generated with primers directed against this gene. RNAi of esc causes an increase in branch number and an expansion of the receptive field of class I neurons. RNAi also causes defects in muscle, alterations in the number of MD neurons, defects in dendrite morphogenesis and reproducible defects in da dendrite development.
Pc-G proteins can silence gene expression at a large number of chromosomal locations, affecting both enhancer-activated and basal w transcription. Repression is observed even with separation distances of up to 3.0kb between target promoters and binding sites for tethered Pc-G proteins.
Evidence of physical interaction between esc and E(z) in vitro and in vivo and coimmunoprecipitation in vivo suggests the proteins are direct partners in Pc-G mediated repression and this relationship has been evolutionarily conserved.
Genetic interactions have been demonstrated between esc, Asx, E(Pc), Pcl, E(z) and sxc. Most duplications of Pc-group genes neither exhibit anterior transformations nor suppress the extra sex comb phenotype of Pc-group mutations, suggesting that not all Pc-group genes behave as predicted by the mass action model. Duplications of E(z) enhance homeotic phenotypes of esc mutants. Flies with increasing doses of esc+ exhibit anterior transformations, but these are not enhanced by mutations in trithorax group genes.
The early expression of esc, nuclear localisation and sequence homology to the WD-40 repeat family are consistent with a specific early role for esc in forging a link between the regulators encoded by segmentation genes and the Pc-group machinery.
esc protein is highly conserved between the D.melanogaster and D.virilis species, particularly the WD motifs. The high degree of conservation suggests that each of the WD repeats is functionally specialised and that this specialisation is highly conserved during evolution. The highly charged N-terminus exhibits the greatest divergence, but even these differences are conservative of its predicted physical properties. Observations suggest the esc protein is functionally compact, nearly every residue making an important contribution to its function.
Heat shock experiments demonstrate the requirement for esc begins between 2 and 4 hours of embryogenesis.
The predicted esc protein contains multiple copies of the WD40 repeat which functions in protein-protein contact in other proteins.
The bithorax complex genes are regulated by the Pc group of genes, acting via 'Pc group response elements' (PREs), that can work even when removed from the normal bithorax complex context. The Pc group products apparently provide stable memory or imprinting of boundaries which are specified by gap and pair-rule regulators.
Distal portions of second and third legs weakly transformed into first leg and wing blade into haltere; transformation partial and variable in hypomorphic allele, esc1. Leg effects autonomous in homozygous clones of hypomorphic or amorphic alleles. Studies with amorphic alleles demonstrate that esc offspring of esc/+ mothers express the leg transformation, but esc zygotes produced by esc mothers die as newly hatched larvae that exhibit drastic homeotic transformations. All abdominal and thoracic and some head segments are transformed into eighth abdominal segments. The effects of the maternal insufficiency partially overcome by the presence in the zygote of a paternally derived esc+ allele, more so by two paternally derived esc+ alleles. Larvae with one paternal esc+ range between normal and transformed phenotype; those with two frequently develop into adults, more than half of which show patchy transformations in abdominal and thoracic segments to more posterior segments.
The Pc group genes are negative regulators of homeotic genes.
esc gene region has been cloned and isolated: a 12kb fragment carries the esc gene flanking sequences required for its proper regulation, as proven by P element mediated transformation.
In the esc- embryo, Ubx transcription is normal early in development, but following gastrulation transcripts appear in ectodermal and mesodermal derivatives of all fourteen parasegments rather than being restricted to parasegments 6-12 as in wild-type.
Embryos lacking the esc gene product show unrestricted expression of most or all bithorax complex genes throughout the body.
Embryos lacking the esc gene product develop into first instar larvae in which most segments, including several head segments and a normally cryptic ninth abdominal segment, display a cuticular pattern approaching that of the normal eighth abdominal segment.
Slifer, 2nd May 1940.