Osser is the first complete algae Ty1/Copia-like retroelement described in the green alga Volvox carteri (Lindauer et al. 1993). Osser constitutes a one-single-sequence clade within Branch 2 of the Ty1/Copia LTR retrotransposons family (Llorens et al. 2009) as it has no phylogenetic relatives to date reported. The full-length Osser genome is 4885 bp in size, including two identical 197-bp LTRs. The internal region of this element presents a Primer Binding Site (PBS) for a tRNAMet, two overlapping Open Reading Frames (ORFs) containing the typical gag and pol domains of Ty1/Copia LTR retrotransposons: gag (in which is present the zinc finger motif of Cys-His type characteristic of the nucleocapside domain), protease, integrase, reverse transcriptase and ribonuclease H; and a Polypurine Tract (PPT) upstream its 3’ LTR (Lindauer et al. 1993).



Figure not to scale. If present, long terminal repeats (LTRs) have been highlighted in blue. Amino acid motifs noted with lines indicate the conserved residues in each protein domain, abbreviations below mean:

MA=matrix PR=protease DU or DUT=dUTPase TM=transmembrane TAV or IBMP=transactivator/viroplasmin or inclusion body matrix protein
CA=capsid RT=reverse transcriptase INT=Integrase CHR=chromodomain
NC=nucleocapsid RH=RNaseH SU=surface MOV=movement protein
PPT=polypurine tract PBS=primer binding site ATF=aphid transmission factor VAP=virion associated protein

Related literature

Genbank accession: 288596
Clade: Osser
Cluster or genus: Undetermined
Branch or class: Branch 2
Family: Ty1/Copia
System: LTR retroelements
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Volvox carteri.jpg
Volvox carteri
Carol Ann Borden, Department of Botany, University of British Columbia
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Welcome to the Gypsy Database (GyDB) an open editable database about the evolutionary relationship of viruses, mobile genetic elements (MGEs) and the genomic repeats where we invite all authors to contribute with their knowledge to improve and expand the topics.
Cite this project:

Llorens, C., Futami, R., Covelli, L., Dominguez-Escriba, L., Viu, J.M., Tamarit, D., Aguilar-Rodriguez, J. Vicente-Ripolles, M., Fuster, G., Bernet, G.P., Maumus, F., Munoz-Pomer, A., Sempere, J.M., LaTorre, A., Moya, A. (2011) The Gypsy Database (GyDB) of Mobile Genetic Elements: Release 2.0 Nucleic Acids Research (NARESE) 39 (suppl 1): D70-D74 doi: 10.1093/nar/gkq1061

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