Characterization of a LINE retroposon dispersed in the genome of three non-sibling Aedes mosquito species.
A family of long interspersed repetitive elements (LINEs) dispersed in the genome of Aedes mosquitoes is described. Basically, full-length copies of the element designated Juan-A are dispersed in the genome of A. aegypti, but some elements are truncated or deleted. Complete Juan-A elements are 4.7 kb long, and their overall genetic organization is similar to that of LINEs from other species in which this class of nonviral retrotransposons has been described. Juan-A elements are terminated at the 3' end by an adenosine(A)-rich sequence and are flanked by target-site duplications. They display two long open reading frames potentially encoding two polypeptides. The first one contains Cys-rich motifs typical of nucleic-acid-binding proteins, while the other shows homology to the reverse transcriptases. These features are characteristic of LINE retroposons and indicate that Juan-A elements can be transposed by reverse transcription of an RNA intermediate. Furthermore, Juan-A retroposons display significant homologies with the Drosophila LINEs Jockey and F, suggesting that all these elements have arisen from a common precursor. The full-length Juan-A copies which are amplified in the genomes of various strains belonging to the three non-sibling species, A. aegypti, A. albopictus and A. polynesiensis, form an internally homogeneous family. These data are interpreted to indicate that active Juan-A retroposons underwent a recent amplification in the strains analyzed. Furthermore, they suggest that these elements have spread by horizontal transfer between the three non-sibling species.
Mouchès
C
C
Laboratoire d'Ecologie Moléculaire, Université de Pau et des Pays de l'Adour, France.
Bensaadi
N
N
Salvado
J C
JC
D000330:Aedes / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D004251:DNA Transposable Elements; D004330:Drosophila / Q000235:genetics; D016678:Genome; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D012190:Retroviridae / Q000235:genetics* / Q000302:isolation & purification; D013045:Species Specificity
D004251:DNA Transposable Elements; D004247:DNA