Micropia: a retrotransposon of Drosophila combining structural features of DNA viruses, retroviruses and non-viral transposable elements.
The retrotransposon micropia was first described from Y-chromosomal fertility genes of Drosophila hydei. Screening a Drosophila melanogaster genomic library yielded several clones representing micropia elements in D. melanogaster. The DNA sequences of two elements from D. hydei (micropia-DhMiF2 and micropia-DhMiF8) and two elements from D. melanogaster (micropia-Dm2 and micropia-Dm11) permitted a detailed analysis of the spatial organization of micropia constituents. Micropia represents the typical gene organization represented by "core"-protein domains followed by a protease, reverse transcriptase, RNase and integrase domain. New features of the micropia family compared with other retrotransposons are: (1) a region of similarity to class I major histocompatibility complex antigens of mammals; (2) only one main open reading frame of about 4000 bases length; (3) a non-protein-coding region of about 500 base-pairs length between the 3' end of the open reading frame and the 5' start of the 3' long terminal repeat. This region includes 32 base-pair tandem repeats; (4) within the long terminal repeats, 82 base-pair tandem repeats with four potential ecdysteroid receptor binding sites. Because micropia combines many evolutionary features of different viruses, non-viral transposable elements, chromosomal genes and repetitive sequence organizations, this retrotransposon may be seen as a "minigenome" reflecting evolutionary principles of the construction of genomic components.
Lankenau
D H
DH
Department of Molecular and Developmental Genetics, Katholieke Universiteit, Nijmegen, The Netherlands.
Huijser
P
P
Jansen
E
E
Miedema
K
K
Hennig
W
W
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004254:DNA Nucleotidyltransferases; D004251:DNA Transposable Elements; D004267:DNA Viruses / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics*; D005796:Genes; D015395:Histocompatibility Antigens Class I; D019426:Integrases; D010447:Peptide Hydrolases; D012194:RNA-Directed DNA Polymerase; D012190:Retroviridae / Q000235:genetics*; D012260:Ribonucleases
D004251:DNA Transposable Elements; D015395:Histocompatibility Antigens Class I; D004254:DNA Nucleotidyltransferases; D019426:Integrases; D012194:RNA-Directed DNA Polymerase; D012260:Ribonucleases; D010447:Peptide Hydrolases