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{{Element
|genbank=[http://www.ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=nucleotide&val=32448682 32448682]
|type=
|genus= Soymovirus
|subfamily= Class 1
|family= Caulimoviridae
|group= LTR retroelements
|description=''Cestrum yellow leaf curling virus'' (CmYLCV), a pararetrovirus closely related to the ''Soybean chlorotic mottle virus'' (SbCMV) - the type species of the genus ''Soymovirus'', ''Caulimoviridae'' family (''International Committee on the Taxonomy of Viruses'' -ICTV- [[Literature:100589|Fauquet ''et al''. 2005]]). This virus was first isolated from the green cestrum (''Cestrum parqui'') a noxious plant (due to its toxicity to livestock, poultry and humans) belonging to the ''Solanaceae'' family ([[Literature:100695|Ragozzino 1974]]). CmYLCV induces pathological alteration on ''Cestrum parqui'' plants. The symptoms of infected plants are characterized from yellow mosaic and curling of leaves to shoot stunting ([[Literature:100695|Ragozzino 1974]]; [[Literature:100693|Stavolone ''et al.'' 2003a]]). Although no insect vector transmission has been yet well demonstrated, it has been observed that healthy ''C. parqui'' plants transplanted in the vicinity of CmYLCV-naturally infected plants acquired the virus and displayed the typical symptoms, suggesting a possible insect-mediated transmission ([[Literature:100693|Stavolone ''et al.'' 2003a]]).

Morphologically, CmYLCVs are isometric virus particles of about 50 nm in diameter with a circular double-stranded DNA genome 8253 bp long ([[Literature:100693|Stavolone ''et al.'' 2003a]]). The genome contains seven putative Open reading frames (ORFs) designated as I, Ib, II, III, IV, V, VI ([[Literature:100602|Hasegawa ''et al''. 1989]]; [[Literature:100603|Mushegian ''et al'', 1995]]; [[Literature:100686|Glasheen ''et al.'' 2002]]; [[Literature:100693|Stavolone ''et al.'' 2003a]]).

ORF I encodes for a cell-to-cell movement (MOV) protein of 312 amino acids (aa) in size ([[Literature:100693|Stavolone ''et al.'' 2003a]]). ORF Ib (called as Ia in the GenBank accession) is a small protein located upstream to an intergenic region that includes the tRNAMet binding site. ORF II (namely here as ORF B) encodes a protein of 202 aa also preserved in other soymoviruses whose function is still unclear. This ORF contains however a putative double α-helix domain similar to that found in the ORF II of CaMV, which is involved in both aphid transmission factor (ATF) trimerization ([[Literature:100699|Hebrard ''et al.'' 2001]]) and interaction with the product of ORF III ([[Literature:100700|Leh ''et al.'' 1999]]). ORF III (namely here as ORF C) encodes for a protein of 178 aa containg a characteristic coiled–coil domain responsible for tetramerization -a conserved feature of ''Caulimovirus'' "virion associated proteins" (VAPs) ([[Literature:100697|Stavolone ''et al.'' 2001]]). However, our sequence analyses indicate that this protein does not show significant similarities with the VAPs of the other ''Caulimoviridae'' species, but it is more related with ORFs C of the other soymoviruses (BRRV and SbCMV) and with the ORF III of the ''Caulimovirus'' RuFDV, whose functions are still unclear. ORF IV encodes the viral coat protein precursor as suggested by both similarity analyses and the presence of a "RNA-binding" motif (C-X-C-X2-C-X4-H-X4-C ) ([[Literature:100596|Llorens ''et al''. 2009]]; [[Literature:100605|Hull 1996]]; [[Literature:8054|Bouhida ''et al.'' 1993]]). ORF V encodes for a pol polyprotein of 643 aa displaying the typical aspartic protease (PR), reverse transcriptase (RT) and RNase H (RH) domains. ORF VI encodes a putative translational transactivator protein (TAV) of 531 aa that contains the conserved sequence also found in the TAV associated genes of other caulimoviruses ([[Literature:100693|Stavolone ''et al.'' 2003a]]; [[Literature:100686|Glasheen ''et al.'' 2002]]; [[Literature:100602|Hasegawa ''et al.'' 1989]]). CmYLCV differs from other ''Soymovirus'' members in the absence of the non-essential ORF VII. The intergenic region (Gap) between TAV and MOV is thus longer than the same region of the remaining known soymoviruses ([[Literature:100603|Mushegian ''et al'', 1995]]; [[Literature:100692|Takemoto and Hibi 2001]]; [[Literature:100686|Glasheen ''et al.'' 2002]]]. Within this intergenic region a novel functional constitutive and highly expressed promoter has been isolated ([[Literature:100696|Stavolone ''et al.'' 2003b]]). This promoter is highly active in callus, meristems and vegetative and reproductive tissues of ''Arabidopsis thaliana'', ''Nicotiana tabacum'', ''Lycopersicon esculentum'', ''Zea mays'' and ''Oryza sativa'' ([[Literature:100696|Stavolone ''et al.'' 2003b]]). The expression levels of this promoter is comparable to, or higher than, the three frequently used promoters in agricultural biotechnology: the ''Cauliflower mosaic virus'' (CaMV) 35S ([[Literature:100701|Fang ''et al.'' 1989]]; [[Literature:100702|Benfey ''et al.'' 1990]]), the synthetic "super-promoter" ([[Literature:100703|Ni ''et al.'' 1995]]) or the maize Ubi1 ([[Literature:100704|Christensen'' et al.'' 1992]])]. Thus, the CmYLCV promoter appears to be a useful tool for biotechnology applications and agricultural research ([[Literature:100696|Stavolone ''et al.'' 2003b]]). The sequence of this promoter is available at Syngenta Biotechnology, Inc. ([http://www.syngentabiotech.com/biomain.aspx www.syngentabiotechnology.com]). Our sequence analyses additionally reveal the presence of an eighth small ORF, located within the ''Gag''-like gene, similar in size and position to the ORF VIII of SbCMV ([[Literature:100602|Hasegawa ''et al.'' 1989]]).
|structure=CmYLCV.png
|structure_legend=(MOV=ORF I; VAP=ORF III; COAT(''Gag'')=ORF IV; POL=ORF V; TAV=ORF VI; solid line=untranslated region)
|host=Cestrum parqui
|hostpic=Cestrum_parqui.jpg
|literature=
|picowner= [http://en.wikipedia.org/wiki/File:Cestrum_parqui.jpg Courtesy of Wikipedia, copyright of the author A.Barra]
}}
[[Category:Element]]

Element:CmYLCV - Revision history

imported>Gydbwiki at 10:25, 6 May 2010