The gene easter is referred to in FlyBase by the symbol Dmel\ea (CG4920, FBgn0000533). It is a protein_coding_gene from Drosophila melanogaster. There is experimental evidence that it has the molecular function: serine-type endopeptidase activity. There is experimental evidence that it is involved in the biological process: zymogen activation; dorsal/ventral axis specification. 86 alleles are reported. The phenotypes of these alleles are annotated with: dorsal closure embryo; embryonic/first instar larval cuticle; extended germ band embryo; embryonic epidermis; head; embryo; denticle belt. It has 2 annotated transcripts and 2 annotated polypeptides. Protein features are: Disulphide knot CLIP; Peptidase S1; Peptidase S1, trypsin family, active site; Peptidase S1A, chymotrypsin-type; Proteinase, regulatory CLIP domain; Trypsin-like cysteine/serine peptidase domain. Summary of modENCODE Temporal Expression Profile: Temporal profile ranges from a peak of high expression to a trough of low expression. Peak expression observed within 00-06 hour embryonic stages. Summary of FlyAtlas Anatomical Expression Data: Expression at moderate levels in the following post-embryonic organs or tissues: adult head, adult crop, larval/adult hindgut, larval trachea, adult ovary, larval carcass. Comments on Affy2 ProbeSet: ProbeSet 1639867_at completely aligns to an exonic region of the only FlyBase-annotated transcript isoform of ea. Gene sequence location is 3R:11154451..11156130.
User Contributed Data
External Summaries
Phenotypic Description from the Red Book (Lindsley
& Zimm 1992)
Gene/Allele symbols may differ
from current usage
ea: easter
Maternal effect lethal; both recessive loss-of-function and dominant gain-of-function alleles female sterile.
Embryos produced by females homozygous for recessive alleles
are dorsalized; lack ventral and lateral elements similar to
embryos produced by dl/dl females; dorsal folds extend around
circumference of embryo; lateral head fold and ventral furrow
fail to form; germ band does not extend, and cuticle forms a
tube with dorsal characteristics throughout. Degree of dorsalization proportional to level of ea expression as demonstrated by hypomorphic and temperature-sensitive alleles.
Temperature sensitive period as demonstrated by ea14 from the
time of pole-cell formation to gastrulation; developmental
Northern blots demonstrate the presence of transcript in the
ovaries and increased levels during the first four hours of
embryonic development followed by a marked decline between
hours four and six. Partial rescue of mutant phenotype
achieved by injection of cytoplasm or poly-A+ RNA from wildtype embryos or embryos from females homozygous for other
dorsal-group mutants; spatial source of donor cytoplasm unimportant; degree of rescue reduced with distance from site of
injection; complete rescue producing viable and fertile adults
achievable with injection of purified ea+ mRNA. tw, a zygotically active member of the dorsal group of genes, is not
expressed in such embryos (Thisse, Stoetzel, El Messal, and
Perrin-Schmidt, 1987, Genes Dev. 1: 709-15); furthermore
strong alleles allow zen expression ventrally where it is not
normally observed (Rushlow, Frasch, Doyle, and Levine, 1987,
Nature 330: 583-86); periodicity of ftz stripes slightly disrupted in embryos from ea mothers (Carroll, Winslow, Twombly,
and Scott, 1987, Development 99: 327-32). Females heterozygous for fully penetrant dominant alleles are sterile; the
offspring of eaD3/+ females display ventralization or lateralization as indicated by lateral extension of the denticle
bands; patches or rings of denticles may encircle the embryo;
however, the mesoderm, the most ventral pattern element, is
not increased; dorsal structures such as filzkorper, antennal
and maxillary sense organs are absent; field of dorsal hairs
greatly reduced. eaD2/+ females are lateralized, producing
embryos that lack presumptive mesoderm and have no ventral
furrow, show dorsoventrally symmetrical folding at gastrulation with the lateral head fold encircling the embryo, and do
not undergo germ band extension. Injection of ea-deficient
embryos with 200 times the quantity of mRNA required for complete rescue does not cause ventralization, indicating that
gain of function alleles are not merely hypomorphic in nature.
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Summary of FlyAtlas Anatomical Expression Data: Expression at moderate levels in the following post-embryonic organs or tissues: adult head, adult crop, larval/adult hindgut, larval trachea, adult ovary, larval carcass.
[download data (TSV)]
Guide to FlyAtlas expression level colors
No expression (0 - 9.999)
Low expression (10 - 99.999)
Moderate expression (100 - 499.999)
High level expression (500 - 999.999)
Very high expression (>999.999)
Linear, scaled to maximum expression level
Tissue
Expression Level
Larval Central Nervous System
12.425
Larval Midgut
18.1
Larval Hindgut
341.3
Larval Malpighian Tubules
5.9
Larval Fat Body
11
Larval Salivary Gland
15.2
Larval Trachea
398.625
Larval Carcass
231.5
Adult Head
110.5
Adult Eye
58.6
Adult Brain
16.8
Adult Thoracic-Abdominal Ganglion
31.7
Adult Crop
340.4
Adult Midgut
17.2
Adult Hindgut
356.7
Adult Malpighian Tubules
11.3
Adult Fat Body
5.6
Adult Salivary Gland
13.5
Adult Heart
5
Adult VirginFemale Spermatheca
42.9
Adult InseminatedFemale Spermatheca
58.5
Adult Ovary
202.4
Adult Testis
11
Adult Male Accessory Gland
4
Adult Carcass
64
Expression Level Scale
None
Low
Moderate
Linear, scaled to Moderate expression
Tissue
Expression Level
Larval Central Nervous System
12.425
Larval Midgut
18.1
Larval Hindgut
341.3
Larval Malpighian Tubules
5.9
Larval Fat Body
11
Larval Salivary Gland
15.2
Larval Trachea
398.625
Larval Carcass
231.5
Adult Head
110.5
Adult Eye
58.6
Adult Brain
16.8
Adult Thoracic-Abdominal Ganglion
31.7
Adult Crop
340.4
Adult Midgut
17.2
Adult Hindgut
356.7
Adult Malpighian Tubules
11.3
Adult Fat Body
5.6
Adult Salivary Gland
13.5
Adult Heart
5
Adult VirginFemale Spermatheca
42.9
Adult InseminatedFemale Spermatheca
58.5
Adult Ovary
202.4
Adult Testis
11
Adult Male Accessory Gland
4
Adult Carcass
64
Expression Level Scale
None
Low
Moderate
High
Linear, scaled to High level expression
Tissue
Expression Level
Larval Central Nervous System
12.425
Larval Midgut
18.1
Larval Hindgut
341.3
Larval Malpighian Tubules
5.9
Larval Fat Body
11
Larval Salivary Gland
15.2
Larval Trachea
398.625
Larval Carcass
231.5
Adult Head
110.5
Adult Eye
58.6
Adult Brain
16.8
Adult Thoracic-Abdominal Ganglion
31.7
Adult Crop
340.4
Adult Midgut
17.2
Adult Hindgut
356.7
Adult Malpighian Tubules
11.3
Adult Fat Body
5.6
Adult Salivary Gland
13.5
Adult Heart
5
Adult VirginFemale Spermatheca
42.9
Adult InseminatedFemale Spermatheca
58.5
Adult Ovary
202.4
Adult Testis
11
Adult Male Accessory Gland
4
Adult Carcass
64
Expression Level Scale
None
Low
Moderate
High
Very high
Linear, scaled to Very high expression
Tissue
Expression Level
Larval Central Nervous System
12.425
Larval Midgut
18.1
Larval Hindgut
341.3
Larval Malpighian Tubules
5.9
Larval Fat Body
11
Larval Salivary Gland
15.2
Larval Trachea
398.625
Larval Carcass
231.5
Adult Head
110.5
Adult Eye
58.6
Adult Brain
16.8
Adult Thoracic-Abdominal Ganglion
31.7
Adult Crop
340.4
Adult Midgut
17.2
Adult Hindgut
356.7
Adult Malpighian Tubules
11.3
Adult Fat Body
5.6
Adult Salivary Gland
13.5
Adult Heart
5
Adult VirginFemale Spermatheca
42.9
Adult InseminatedFemale Spermatheca
58.5
Adult Ovary
202.4
Adult Testis
11
Adult Male Accessory Gland
4
Adult Carcass
64
Expression Level Scale
Very high
log, scaled to maximum expression level
Tissue
Expression Level
Larval Central Nervous System
12.425
Larval Midgut
18.1
Larval Hindgut
341.3
Larval Malpighian Tubules
5.9
Larval Fat Body
11
Larval Salivary Gland
15.2
Larval Trachea
398.625
Larval Carcass
231.5
Adult Head
110.5
Adult Eye
58.6
Adult Brain
16.8
Adult Thoracic-Abdominal Ganglion
31.7
Adult Crop
340.4
Adult Midgut
17.2
Adult Hindgut
356.7
Adult Malpighian Tubules
11.3
Adult Fat Body
5.6
Adult Salivary Gland
13.5
Adult Heart
5
Adult VirginFemale Spermatheca
42.9
Adult InseminatedFemale Spermatheca
58.5
Adult Ovary
202.4
Adult Testis
11
Adult Male Accessory Gland
4
Adult Carcass
64
Expression Level Scale
None
Low
Moderate
High
log, scaled to Moderate expression
Tissue
Expression Level
Larval Central Nervous System
12.425
Larval Midgut
18.1
Larval Hindgut
341.3
Larval Malpighian Tubules
5.9
Larval Fat Body
11
Larval Salivary Gland
15.2
Larval Trachea
398.625
Larval Carcass
231.5
Adult Head
110.5
Adult Eye
58.6
Adult Brain
16.8
Adult Thoracic-Abdominal Ganglion
31.7
Adult Crop
340.4
Adult Midgut
17.2
Adult Hindgut
356.7
Adult Malpighian Tubules
11.3
Adult Fat Body
5.6
Adult Salivary Gland
13.5
Adult Heart
5
Adult VirginFemale Spermatheca
42.9
Adult InseminatedFemale Spermatheca
58.5
Adult Ovary
202.4
Adult Testis
11
Adult Male Accessory Gland
4
Adult Carcass
64
Expression Level Scale
None
Low
Moderate
High
log, scaled to High level expression
Tissue
Expression Level
Larval Central Nervous System
12.425
Larval Midgut
18.1
Larval Hindgut
341.3
Larval Malpighian Tubules
5.9
Larval Fat Body
11
Larval Salivary Gland
15.2
Larval Trachea
398.625
Larval Carcass
231.5
Adult Head
110.5
Adult Eye
58.6
Adult Brain
16.8
Adult Thoracic-Abdominal Ganglion
31.7
Adult Crop
340.4
Adult Midgut
17.2
Adult Hindgut
356.7
Adult Malpighian Tubules
11.3
Adult Fat Body
5.6
Adult Salivary Gland
13.5
Adult Heart
5
Adult VirginFemale Spermatheca
42.9
Adult InseminatedFemale Spermatheca
58.5
Adult Ovary
202.4
Adult Testis
11
Adult Male Accessory Gland
4
Adult Carcass
64
Expression Level Scale
None
Low
Moderate
High
Very high
log, scaled to Very high expression
Tissue
Expression Level
Larval Central Nervous System
12.425
Larval Midgut
18.1
Larval Hindgut
341.3
Larval Malpighian Tubules
5.9
Larval Fat Body
11
Larval Salivary Gland
15.2
Larval Trachea
398.625
Larval Carcass
231.5
Adult Head
110.5
Adult Eye
58.6
Adult Brain
16.8
Adult Thoracic-Abdominal Ganglion
31.7
Adult Crop
340.4
Adult Midgut
17.2
Adult Hindgut
356.7
Adult Malpighian Tubules
11.3
Adult Fat Body
5.6
Adult Salivary Gland
13.5
Adult Heart
5
Adult VirginFemale Spermatheca
42.9
Adult InseminatedFemale Spermatheca
58.5
Adult Ovary
202.4
Adult Testis
11
Adult Male Accessory Gland
4
Adult Carcass
64
Expression Level Scale
None
Low
Moderate
High
Very high
Heatmap
Tissue
Expression Level
Larval Central Nervous System
Larval Midgut
Larval Hindgut
Larval Malpighian Tubules
Larval Fat Body
Larval Salivary Gland
Larval Trachea
Larval Carcass
Adult Head
Adult Eye
Adult Brain
Adult Thoracic-Abdominal Ganglion
Adult Crop
Adult Midgut
Adult Hindgut
Adult Malpighian Tubules
Adult Fat Body
Adult Salivary Gland
Adult Heart
Adult VirginFemale Spermatheca
Adult InseminatedFemale Spermatheca
Adult Ovary
Adult Testis
Adult Male Accessory Gland
Adult Carcass
FlyAtlas Organ/Tissue Expression, larval vs. adult
Summary of modENCODE Temporal Expression Profile: Temporal profile ranges from a peak of high expression to a trough of low expression. Peak expression observed within 00-06 hour embryonic stages.
[download data (TSV)]
Please Note FlyBase no
longer curates genomic clone accessions so this list
may not be complete
cDNA Clones ( 16 )
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.
A dorsalising activity for the heterologous ea, spz and Tl proteins in UV-ventralised Xenopus embryos is demonstrated: ea dorsalises UV-treated X.laevis embryos. The activity is inhibited by co-injection of a dominant cact variant.
Shows particularly robust cycling of transcription in adult heads, as assessed by expression analysis using high density oligonucleotide arrays with probe generated during three 12-point time course experiments over the course of 6 days. Shows significant change of expression pattern in circadian mutant background; decreased expression in per01, tim01 and ClkJrk background.
ea can directly cleave spz at a unique position, the spz carboxy-terminal fragment generated has the biological and biochemical properties of the polarising activity of spz, it exists as a disulfide-linked dimer and appears to share structural similarities with the nerve growth factor and the neurotrophin family of growth factor ligands.
The zymogen form of ea is processed in vivo by a proteolytic cleavage event that requires three upstream proteases. Processed ea is present in extremely low amounts in the early embryo because it is rapidly converted into a high molecular mass complex, which may contain a protease inhibitor. ea zymogen activation is also controlled by a negative feedback loop from dl.
The embryonic regulatory pathway, comprising the gene products between spz and cact (Tl, tub and pll) but not the genes acting upstream or downstream (ea and dl), is involved in the induction of the Drs gene in adults. Neither ea or snk are required for the control of Drs gene expression.
Spatial regulation of ea activity by localized zymogen activation is a key initial event in defining the polarity of the dorsal-ventral embryonic pattern.
In the absence of ea activity in the perivitelline fluid no Tl ligand is detected suggesting that ea activity is involved in the production of the Tl ligand.
Involved in the regulatory hierarchy responsible for the asymmetric distribution and function of zygotic regulatory gene products along the DV axis of early embryos.
Maternal effect lethal; both recessive loss-of-function and dominant gain-of-function (eaD) alleles female sterile. Embryos produced by females homozygous for recessive alleles are dorsalized; lack ventral and lateral elements similar to embryos produced by dl/dl females; dorsal folds extend around circumference of embryo; lateral head fold and ventral furrow fail to form; germ band does not extend and cuticle forms a tube with dorsal characteristics throughout. Degree of dorsalization proportional to level of ea expression as demonstrated by hypomorphic and temperature-sensitive alleles. Temperature sensitive period as demonstrated by ea14 from the time of pole-cell formation to gastrulation; developmental Northern blots demonstrate the presence of transcript in the ovaries and increased levels during the first four hours of embryonic development followed by a marked decline between hours four and six. Partial rescue of mutant phenotype achieved by injection of cytoplasm or poly(A)+ RNA from wild-type embryos or embryos from females homozygous for other dorsal-group mutants; spatial source of donor cytoplasm unimportant; degree of rescue reduced with distance from site of injection; complete rescue producing viable and fertile adults achievable with injection of purified ea+ mRNA. tw, a zygotically active member of the dorsal group of genes, is not expressed in such embryos (Thisse, Stoetzel, El Messal and Perrin-Schmidt, 1987); furthermore strong alleles allow zen expression ventrally where it is not normally observed (Rushlow, Frasch, Doyle and Levine, 1987); periodicity of ftz stripes slightly disrupted in embryos from ea mothers (Carroll, Winslow, Twombly and Scott, 1987). Females heterozygous for fully penetrant dominant alleles are sterile; the offspring of eaD3/+ females display ventralization or lateralization as indicated by lateral extension of the denticle bands; patches or rings of denticles may encircle the embryo; however, the mesoderm, the most ventral pattern element, is not increased; dorsal structures such as filzkorper, antennal and maxillary sense organs are absent; field of dorsal hairs greatly reduced. eaD2/+ females are lateralized, producing embryos that lack presumptive mesoderm and have no ventral furrow, show dorsoventrally symmetrical folding at gastrulation with the lateral head fold encircling the embryo and do not undergo germ band extension. Injection of ea-deficient embryos with 200 times the quantity of mRNA required for complete rescue does not cause ventralization, indicating that gain of function alleles are not merely hypomorphic in nature.