The gene egalitarian is referred to in FlyBase by the symbol Dmel\egl (CG4051, FBgn0000562). It is a protein_coding_gene from Drosophila melanogaster. There is experimental evidence that it has the molecular function: mRNA binding. There is experimental evidence that it is involved in the biological process: germarium-derived oocyte fate determination; intracellular mRNA localization; oogenesis; mRNA transport. 28 alleles are reported. The phenotypes of these alleles are annotated with: multicellular structure; organ system; anatomical structure; organelle; intracellular organelle part; portion of tissue; intracellular non-membrane-bounded organelle; vitellarium; nuclear part; centrosome; synapse; karyosome. It has one annotated transcript and one annotated polypeptide. Protein features are: 3'-5' exonuclease domain; Ribonuclease H-like 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: Many larval and adult organs/tissues expressed at moderate levels. Expression at high levels in the following post-embryonic organs or tissues: adult crop, larval/adult salivary gland. Expression at moderate levels in the following post-embryonic organs or tissues: adult head, adult eye, adult central nervous system, larval/adult midgut, larval/adult hindgut, larval/adult Malpighian tubules, adult fat body, larval trachea, adult female reproductive system, adult male accessory gland, larval/adult carcass. Comments on Affy2 ProbeSet: ProbeSet 1641303_at completely aligns to an exonic region of the only FlyBase-annotated transcript isoform of egl. Gene sequence location is 2R:19622427..19634348.
User Contributed Data
Phenotypic Description from the Red Book (Lindsley
& Zimm 1992)
Gene/Allele symbols may differ
from current usage
egl: egalitarian (T. Schupbach)
Female sterile. Defect in cell fate detectable in
anterior germarium. In contrast to wild-type, in all egl
alleles all sixteen cells per cyst enter pachytene; subsequently all sixteen revert to nurse-cell morphology and
behavior (Carpenter). Egg chambers increase in volume along
the ovariole, but do not take up yolk. No chorion is formed.
BicD/+ females simultaneously heterozygous for egl1 or egl2
fail to form double-abdomen embryos (Mohler and Wieschaus,
1986, Genetics 112: 803-22).
Recent Updates
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FB2013_03
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egl RNA is enriched in single cells when the 16-cell cyst forms in region 2A of the germarium. Between stages S2 and S7, egl RNA is concentrated at the posterior cortex of the oocyte. As the oocyte starts to accumulate yolk, egl transcripts localize to an anterior ring at the nurse cell-oocyte boundary. By stage S10, they are distributed evenly throughout the oocyte and persist in the oocyte until early embryogenesis.
The BicD and egl proteins, as previously described for the orb protein, accumulate in the presumptive oocyte following fusome disassembly in germarium region 2a during oocyte specification and are relocalized to the posterior of the oocyte between germarium regions 2b and 3 during oocyte polarization.
egl protein is first detected in the germarium and is evenly distributed in the newly formed 16-cell cyst. By stage S1 of oogenesis, it localizes to a single cell, the future oocyte. From stages S2 to S7 egl protein is enriched at the posterior cortex of the oocyte, wherever the oocyte abuts the follicle cells. At stage S8, it shifts to the anterior cortex in a ring around the margin of the oocyte where the oocyte, nurse cells, and follicle cells meet. Staining is particularly pronounced around the oocyte nucleus. No protein is detec ed in the oocyte after stage S10. egl protein distribution in oocytes closely resembles the distribution of the minus end of microtubules. It was shown that disrupting microtubule organization abolishes egl protein localization. In addition, egl protein and BcD protein were found to have identical distributions during all stages of oogenesis. Localization of egl protein depends on BicD protein and vice versa.
Summary of FlyAtlas Anatomical Expression Data: Many larval and adult organs/tissues expressed at moderate levels. Expression at high levels in the following post-embryonic organs or tissues: adult crop, larval/adult salivary gland. Expression at moderate levels in the following post-embryonic organs or tissues: adult head, adult eye, adult central nervous system, larval/adult midgut, larval/adult hindgut, larval/adult Malpighian tubules, adult fat body, larval trachea, adult female reproductive system, adult male accessory gland, larval/adult 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
91.125
Larval Midgut
422.4
Larval Hindgut
396.7
Larval Malpighian Tubules
304.3
Larval Fat Body
93
Larval Salivary Gland
552.2
Larval Trachea
214.25
Larval Carcass
236.8
Adult Head
188.8
Adult Eye
189.225
Adult Brain
112.4
Adult Thoracic-Abdominal Ganglion
178.5
Adult Crop
505.2
Adult Midgut
221.6
Adult Hindgut
328.7
Adult Malpighian Tubules
318.3
Adult Fat Body
140
Adult Salivary Gland
653.2
Adult Heart
90.3
Adult VirginFemale Spermatheca
129.8
Adult InseminatedFemale Spermatheca
151.5
Adult Ovary
322.3
Adult Testis
30.7
Adult Male Accessory Gland
137.2
Adult Carcass
239.1
Expression Level Scale
None
Low
Moderate
High
Linear, scaled to Moderate expression
Tissue
Expression Level
Larval Central Nervous System
91.125
Larval Midgut
422.4
Larval Hindgut
396.7
Larval Malpighian Tubules
304.3
Larval Fat Body
93
Larval Salivary Gland
(552.2)
Larval Trachea
214.25
Larval Carcass
236.8
Adult Head
188.8
Adult Eye
189.225
Adult Brain
112.4
Adult Thoracic-Abdominal Ganglion
178.5
Adult Crop
505.2
Adult Midgut
221.6
Adult Hindgut
328.7
Adult Malpighian Tubules
318.3
Adult Fat Body
140
Adult Salivary Gland
(653.2)
Adult Heart
90.3
Adult VirginFemale Spermatheca
129.8
Adult InseminatedFemale Spermatheca
151.5
Adult Ovary
322.3
Adult Testis
30.7
Adult Male Accessory Gland
137.2
Adult Carcass
239.1
Expression Level Scale
None
Low
Moderate
High
Linear, scaled to High level expression
Tissue
Expression Level
Larval Central Nervous System
91.125
Larval Midgut
422.4
Larval Hindgut
396.7
Larval Malpighian Tubules
304.3
Larval Fat Body
93
Larval Salivary Gland
552.2
Larval Trachea
214.25
Larval Carcass
236.8
Adult Head
188.8
Adult Eye
189.225
Adult Brain
112.4
Adult Thoracic-Abdominal Ganglion
178.5
Adult Crop
505.2
Adult Midgut
221.6
Adult Hindgut
328.7
Adult Malpighian Tubules
318.3
Adult Fat Body
140
Adult Salivary Gland
653.2
Adult Heart
90.3
Adult VirginFemale Spermatheca
129.8
Adult InseminatedFemale Spermatheca
151.5
Adult Ovary
322.3
Adult Testis
30.7
Adult Male Accessory Gland
137.2
Adult Carcass
239.1
Expression Level Scale
None
Low
Moderate
High
Very high
Linear, scaled to Very high expression
Tissue
Expression Level
Larval Central Nervous System
91.125
Larval Midgut
422.4
Larval Hindgut
396.7
Larval Malpighian Tubules
304.3
Larval Fat Body
93
Larval Salivary Gland
552.2
Larval Trachea
214.25
Larval Carcass
236.8
Adult Head
188.8
Adult Eye
189.225
Adult Brain
112.4
Adult Thoracic-Abdominal Ganglion
178.5
Adult Crop
505.2
Adult Midgut
221.6
Adult Hindgut
328.7
Adult Malpighian Tubules
318.3
Adult Fat Body
140
Adult Salivary Gland
653.2
Adult Heart
90.3
Adult VirginFemale Spermatheca
129.8
Adult InseminatedFemale Spermatheca
151.5
Adult Ovary
322.3
Adult Testis
30.7
Adult Male Accessory Gland
137.2
Adult Carcass
239.1
Expression Level Scale
Very high
log, scaled to maximum expression level
Tissue
Expression Level
Larval Central Nervous System
91.125
Larval Midgut
422.4
Larval Hindgut
396.7
Larval Malpighian Tubules
304.3
Larval Fat Body
93
Larval Salivary Gland
552.2
Larval Trachea
214.25
Larval Carcass
236.8
Adult Head
188.8
Adult Eye
189.225
Adult Brain
112.4
Adult Thoracic-Abdominal Ganglion
178.5
Adult Crop
505.2
Adult Midgut
221.6
Adult Hindgut
328.7
Adult Malpighian Tubules
318.3
Adult Fat Body
140
Adult Salivary Gland
653.2
Adult Heart
90.3
Adult VirginFemale Spermatheca
129.8
Adult InseminatedFemale Spermatheca
151.5
Adult Ovary
322.3
Adult Testis
30.7
Adult Male Accessory Gland
137.2
Adult Carcass
239.1
Expression Level Scale
None
Low
Moderate
High
Very high
log, scaled to Moderate expression
Tissue
Expression Level
Larval Central Nervous System
91.125
Larval Midgut
422.4
Larval Hindgut
396.7
Larval Malpighian Tubules
304.3
Larval Fat Body
93
Larval Salivary Gland
552.2
Larval Trachea
214.25
Larval Carcass
236.8
Adult Head
188.8
Adult Eye
189.225
Adult Brain
112.4
Adult Thoracic-Abdominal Ganglion
178.5
Adult Crop
505.2
Adult Midgut
221.6
Adult Hindgut
328.7
Adult Malpighian Tubules
318.3
Adult Fat Body
140
Adult Salivary Gland
653.2
Adult Heart
90.3
Adult VirginFemale Spermatheca
129.8
Adult InseminatedFemale Spermatheca
151.5
Adult Ovary
322.3
Adult Testis
30.7
Adult Male Accessory Gland
137.2
Adult Carcass
239.1
Expression Level Scale
None
Low
Moderate
High
log, scaled to High level expression
Tissue
Expression Level
Larval Central Nervous System
91.125
Larval Midgut
422.4
Larval Hindgut
396.7
Larval Malpighian Tubules
304.3
Larval Fat Body
93
Larval Salivary Gland
552.2
Larval Trachea
214.25
Larval Carcass
236.8
Adult Head
188.8
Adult Eye
189.225
Adult Brain
112.4
Adult Thoracic-Abdominal Ganglion
178.5
Adult Crop
505.2
Adult Midgut
221.6
Adult Hindgut
328.7
Adult Malpighian Tubules
318.3
Adult Fat Body
140
Adult Salivary Gland
653.2
Adult Heart
90.3
Adult VirginFemale Spermatheca
129.8
Adult InseminatedFemale Spermatheca
151.5
Adult Ovary
322.3
Adult Testis
30.7
Adult Male Accessory Gland
137.2
Adult Carcass
239.1
Expression Level Scale
None
Low
Moderate
High
Very high
log, scaled to Very high expression
Tissue
Expression Level
Larval Central Nervous System
91.125
Larval Midgut
422.4
Larval Hindgut
396.7
Larval Malpighian Tubules
304.3
Larval Fat Body
93
Larval Salivary Gland
552.2
Larval Trachea
214.25
Larval Carcass
236.8
Adult Head
188.8
Adult Eye
189.225
Adult Brain
112.4
Adult Thoracic-Abdominal Ganglion
178.5
Adult Crop
505.2
Adult Midgut
221.6
Adult Hindgut
328.7
Adult Malpighian Tubules
318.3
Adult Fat Body
140
Adult Salivary Gland
653.2
Adult Heart
90.3
Adult VirginFemale Spermatheca
129.8
Adult InseminatedFemale Spermatheca
151.5
Adult Ovary
322.3
Adult Testis
30.7
Adult Male Accessory Gland
137.2
Adult Carcass
239.1
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 ( 56 )
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.
egl protein colocalises with BicD protein to the oocyte in three stages that correlate with the stepwise polarization of the oocyte. Immunoprecipitation experiments show that both proteins are part of a protein complex. Results propose that the egl-BicD protein complex links microtubule polarity and RNA transport.
Oocyte determination requires egl function in the germ line, but not in the surrounding follicle cells. During early oogenesis the egl-BicD protein complex is required to transport factors promoting oocyte differentiation; during later stages the complex directs the sorting of RNA molecules required for anterior-posterior and dorsoventral patterning of the embryo.
The egl locus is responsible for two functions in cell fate choice in oogenesis: early on it is necessary for inhibition of meiotic entry in the "obligate" pro-nurse cells; later it is necessary for meiotic maintenance in the "winning" pro-oocyte. Both roles can be attributed to a single function by invoking gradients through the early cyst; the egl+ function appears to be required for the normal function of these gradients.
Recessive mutations at egl and BicD, and microtubule assembly inhibitors, disrupt the formation and maintenance of the single polarized microtubule cytoskeleton that connects the oocyte to the 15 nurse cells at the time the oocyte is determined.
Alleles of egl and BicD were used to show that the differentiation of an oocyte is required for maintainance but not establishment of follicle polarity.