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General Information
D. melanogaster
Feature type
FlyBase ID
Sequences and Components
Complete element (bp)

to 5kb

Terminal repeat (bp)
Component genes
Sequence Accessions
GenBank Nucleotide - A collection of sequences from several sources, including GenBank, RefSeq, TPA, and PDB.
Sequence Ontology (SO)
Insertions and Copy Number
Copy number and comments


55 in euchromatin of Release 3 genome annotation, of which 30 are full length.

Target Site Duplication
Size (bp)


Curated drosophilid orthologs

The Doc element is transcribed as a full-length 5kb transcript which encodes two open reading frames (ORFs). Doc\gag (ORF1) encodes an RNA-binding protein and Doc\RTase (ORF2) encodes a reverse transcriptase. The RNA is localised on the Drosophila oocyte cytoskeleton.

Changes introduced in the promoter regions of distinct LINEs allows transcriptional activators to stimulate cryptic Inr modules. The response of different promoter constructs to the same enhancer is significantly influenced by the number, position and type of core elements present.

F-element, I-element and Doc basal promoters share the same architecture and functional organisation.

Correlations between the rate of transposition and TE copy number are determined for Doc and are found to be positive.

Doc elements are located in both euchromatin and heterochromatin.

One of a class of genes with TATA-less promoters that have the conserved DPE sequence.

Distinct cis-acting DNA elements, clustered in a 50bp long DNA region located at the 5' end of unit-length Doc copies, cooperate to control RNA initiation. Sequences located 200bp downstream from the 5' end inhibit expression in a position and orientation-dependent manner. Inhibition appears to be due to reduced translation rather that to impaired synthesis.

The distribution of transposable elements within heterochromatin indicates that they are major structural components of the heterochromatin.

Ectopic recombination can occur between two Doc elements.

The Doc retrotransposon has been found unstable in certain stocks.

Closely related to I-element, F-element, G-element and jockey element.

There is no sequence homology between the ends of the Doc element. Different Doc elements are conserved at the 3' end (which terminates with a polyadenylation signal followed by a stretch of oligo-A), but may be truncated at the 5' end, suggesting a mechanism of transposition via an RNA intermediate.

Doc elements lie at both break points of the Antp73b inversion; these elements lie in inverted orientation and the inversion probably resulted from recombination between them.

First described as an insertion in the BXC region on a chromosome carrying the Ubxbx-3 mutation, although it is not responsible for the mutant phenotype.

Other Information
External Crossreferences and Linkouts ( 8 )
GenBank Nucleotide - A collection of sequences from several sources, including GenBank, RefSeq, TPA, and PDB.
Synonyms and Secondary IDs (12)
Reported As
Symbol Synonym
Doc element
doc element
Secondary FlyBase IDs
  • FBgn0000481
  • FBtp0011424
References (175)