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 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 Mobile DNA II. (Craig et al. 2002)

Genbank accession: AB062507 Clade: Pyret Cluster or genus: Fungi and vertebrates Branch or class: Chromoviruses Family: Ty3/Gypsy System: LTR retroelements Host: Explore the Tree Life Project 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 Browse all elements