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FB2026_01
,
released March 12, 2026
s18, s18-1, ACE3
Please see the JBrowse view of Dmel\Cp18 for information on other features
To submit a correction to a gene model please use the Contact FlyBase form
AlphaFold produces a per-residue confidence score (pLDDT) between 0 and 100. Some regions with low pLDDT may be unstructured in isolation.
Gene model reviewed during 5.46
0.75 (northern blot)
There is only one protein coding transcript and one polypeptide associated with this gene
18 (kD observed)
172 (aa); 15 (kD)
172 (aa)
Click to get a list of regulatory features (enhancers, TFBS, etc.) and gene disruptions (point mutations, indels, etc.) within or overlapping Dmel\Cp18 using the Feature Mapper tool.
The testis specificity index was calculated from modENCODE tissue expression data by Vedelek et al., 2018 to indicate the degree of testis enrichment compared to other tissues. Scores range from -2.52 (underrepresented) to 5.2 (very high testis bias).
No transcripts were detected by Northern analysis.
A moderate level of RNA was detected by Northern analysis.
Low levels of RNA were detected by Northern analysis.
Cp18 is expressed in all follicle cells, except for those associated with nurse cell remnants, and those at the tip of the micropyle.
Cp18 transcript first appears in stage S11 of oogenesis, and expression peaks at stage S13-S14.
Signal is transiently detected with Cp18 protein antibody in the vitelline membrane of stage S10 egg chambers, but as Cp18 protein is not detected before stage S13 in Western blots, this signal might represent cross reactivity with another protein. Cp18 protein is detected in secretory granules of follicle cells and in the endochorion in late stage S13-early stage S14 egg chambers. In mid to late stage S14, Cp18 protein is found throughout the endochorion.
The six major chorion bands are dramatically reduced in follicles of Mcm6K1214, mus101K451 and fs(1)A1059K1 mutants. No reduction of major chorion bands is seen in swa6 although some affects are seen in higher molecular weight components.
JBrowse - Visual display of RNA-Seq signals
View Dmel\Cp18 in JBrowse3-26
3-20.9
Please Note FlyBase no longer curates genomic clone accessions so this list may not be complete
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 JBrowse 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.
In a sample of 79 genes with multiple introns, 33 showed significant heterogeneity in G+C content among introns of the same gene and significant positive correspondence between the intron and the third codon position G+C content within genes. These results are consistent with selection adding against preferred codons at the start of genes.
s-18 Flanking gypsy\su(Hw)BRs can create a chromosomal domain permissible for activity of the chorion gene DNA replication origin, DNA replication is dramatically protected from position effects. Inclusion of only a single gypsy\su(Hw)BR does not detectably protect chorion gene DNA replication origin from position effects.
Germline transformation of constructs containing chimeric combinations of D.melanogaster and D.grimshawi Cp18 sequences have been used to map the cis-regulatory elements responsible for the developmental expression of Cp18. Ecol\lacZ reporter gene constructs suggest there may be two activators of Cp18 expression upstream of map position -285, and one downstream and one upstream of map position -442.
Primarily regulated at the transcriptional level.
5' flanking sequence conservation of Cp18 is very strong between species and extends further upstream than that for Cp15, Cp16 or Cp19. Chimeric transposons of D.melanogaster and D.grimshawi reveal that the amplification control element of D.grimshawi can support amplification in D.melanogaster.
Sequence analysis of Cp15, Cp18 and Cp19 has led to the identification of a specific DNA element that may control tissue specificity of amplification. Sequences have also been found that may recognize DNA-binding proteins and so function in regulating the amplification or expression of the chorion genes.
A specific 3.8kb genomic fragment from the chorion gene cluster at 66D retains the ability to amplify during oogenesis when removed to other locations in the genome.
The most 5' of four chorion-protein genes in a 6-kb sequence; encodes S18-1 estimated at 18,000 daltons.
The most 5' of four chorion-protein genes in a 6-kb sequence; encodes S18-1 estimated at 15,600 daltons.