Element:Pyret

Description

Pyret is a LTR retrotransposon characterized in Magnaporthe grisea (Nakayashiki et al. 2001). Pyret belongs to the branch "Chromoviridae" (Marín and Lloréns 2000), term suggested (Marín and Lloréns 2000) to describe the Ty3/Gypsy elements bearing chromodomain-integrases (Malik and Eickbush 1999). The chromovirus branch is probably the most ancient phylogenetic pattern of Ty3/Gypsy retroelements (Gorinsek, Gubensek and Kordis 2004; 2005; Kordis 2005).

The genomic structure of Pyret is 7.2 Kb in size, including LTRs of 475 nt. The internal region displays a Primer Binding Site (PBS), a single ORF gag-pol, and a Polypurine Tract (PPT) adjacent to the 3´LTR (Nakayashiki et al. 2001). This element presents a detectable chromodomain at the C-terminal end of the integrase domain. The PBS of fungi and vertebrate chromoviruses, differs significantly from that used by plant chromoviruses; while plant chromoviruses use a methionine starting tRNA (iMet), fungi and vertebrate chromoviruses use their own self-priming mechanism to start the reverse transcription (Levin 1995 ; Butler et al. 2001).

Structure

Pyret.png


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: AB062507
Clade: Pyret
Cluster or genus: Fungi and vertebrates
Branch or class: Chromoviruses
Family: Ty3/Gypsy
System: LTR retroelements
Host:
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Magnaporthe grisea.gif
Magnaporthe grisea
Image, courtesy of Richard J Howard of DuPont Experimental Station reprinted, with permission, from the Annual Review of Microbiology, Volume 50, Copyright 1996 by Annual Reviews
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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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