Pao is a LTR retrotransposon described in the genome of the domestic silkworm Bombyx mori and its name derives from the Chinese word for “running” (Xiong et al. 1993). Approximately 40 copies of Pao elements are present in the genome with most located outside the ribosomal DNA (rDNA) units (Xiong et al. 1993). Pao gives the name and belongs to Pao clade (Copeland et al. 2005) within Branch 2 of the Bel/Pao family (Llorens et al. 2009). The genome of Pao is about of 4.8 Kb in size (4791 bp in lenght), including LTRs of 629 nt. The internal coding region displays one or two Primer Binding Site (PBS), complementary to a tRNATyr, a single 1158 amino acids ORF for gag and pol genes, and a Polypurine Tract (PPT) adjacent to the 3´LTR. The gag polyprotein presents three CCHC (Cysteine zinc finger array) motifs characteristic of the nucleocapsid domain, while pol shows absence of Integrase and part RNase H (Xiong 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

Mobile DNA II. (Craig et al. 2002)

Genbank accession: 972521
Clade: Pao
Cluster or genus: Undetermined
Branch or class: Branch 2
Family: Bel/Pao
System: LTR retroelements
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Bombyx mori.jpg
Bombyx mori
Image, Laura Covelli,
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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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