Description
Strongylocentrotus purpuratus Mag element (SPM) is a Ty3/Gypsy LTR retrotransposon described in the genome of Strongylocentrotus purpuratus (Llorens et al 2009). SPM belongs, along with other LTR retrotransposons, to Mag a large Ty3/Gypsy cluster widely distributed in both protostomes and deuterostomes (for more details, see Malik and Eickbush 1999; Volff et al. 2001; Tubio, Naveira and Costas 2004). The genomic structure of SPM is 5.2 Kb in size including LTRs of 0.13 kb. The internal region of this element displays a Primer Binding Site (PBS), three Open Reading Frames (ORFs) that code for gag, protease, and pol (RT- RNAseH-INT) polyprotein domains, and a Polypurine Tract (PPT) adjacent to the 3´LTR.
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
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PR=protease
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DU or DUT=dUTPase
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TM=transmembrane
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TAV or IBMP=transactivator/viroplasmin or inclusion body matrix protein
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| CA=capsid
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RT=reverse transcriptase
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INT=Integrase
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CHR=chromodomain
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| NC=nucleocapsid
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RH=RNaseH
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SU=surface
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MOV=movement protein
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| PPT=polypurine tract
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PBS=primer binding site
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ATF=aphid transmission factor
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VAP=virion associated protein
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Related literature
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