Disease relevance of Geminiviridae

• By contrast, ADK activity is increased after inoculation of plants with diverse RNA viruses or a geminivirus lacking a functional L2 gene [1].
• The geminivirus, tomato golden mosaic virus (TGMV), encodes one protein, AL1, that is absolutely required for viral DNA replication [2].
• The functional properties of proteins [capsid protein (CP), V1, and C4] potentially involved with movement of the monopartite begomovirus, Tomato yellow leaf curl virus (TYLCV), were investigated using microinjection of Escherichia coli expressed proteins and transient expression of GFP fusion proteins [3].

High impact information on Geminiviridae

• We report here that the BL1 protein of bean dwarf mosaic geminivirus moves extensively from cell to cell, increases mesophyll plasmodesmal size exclusion limit, and potentiates the movement of double-stranded DNA from cell to cell [4].
• Geminivirus replication enhancer (REn) proteins dramatically increase the accumulation of viral DNA species by an unknown mechanism [5].
• Together, these observations suggest that metabolic alterations mediated by SNF1 are an important component of innate antiviral defenses and that the inactivation of ADK and SNF1 by the geminivirus proteins represents a dual strategy to counter this defense [1].
• To understand how geminiviruses defeat host mechanisms that limit infectivity, we searched for cellular proteins that interact with AL2 and L2 [1].
• The geminivirus BR1 movement protein binds single-stranded DNA and localizes to the cell nucleus [6].

Chemical compound and disease context of Geminiviridae

• Using the GFP-dsGFP system, we demonstrate here that codelivery of a construct expressing an inverted repeat ADK RNA (dsADK), or addition of an ADK inhibitor (the adenosine analogue A-134974), suppresses GFP-directed silencing in a manner similar to the geminivirus proteins [7].
• Together, these results suggest that helix 4 and the conserved leucine residue are part of a pRBR-binding interface in begomovirus replication proteins [8].
• In contrast to the putative C4 proteins of monpartite geminiviruses, TGMV AL4, if it is expressed, is either non-functional, or functionally redundant with an essential TGMV gene product [9].
• Additionally, some of the early proteins (the AL2 protein of subgroup III, and the RepA (formerly known as C1) or Rep (C1:C2) proteins of subgroup I geminiviruses) can function as transcriptional activators of virion- (V-)sense gene expression [10].
• Amino acid sequences predicted from three (V2, C1 and C2) of these ORFs showed significant homology with the corresponding ORFs of other geminiviruses infecting monocots [11].

Biological context of Geminiviridae

• These results show that ATP binding by the Rep protein of geminiviruses is required for its function in viral DNA replication [12].
• Differential roles of AC2 and AC4 of cassava geminiviruses in mediating synergism and suppression of posttranscriptional gene silencing [13].
• The initiation of RCR of the bipartite genome of a geminivirus, Indian mung bean yellow mosaic virus (IMYMV), is mainly controlled by viral protein Rep (or AL1 or AC1) [14].
• The geminivirus replication factor AL1 interacts with the plant retinoblastoma-related protein (pRBR) to modulate host gene expression [8].
• A symptom variant of beet curly top geminivirus produced by mutation of open reading frame C4 [15].

Anatomical context of Geminiviridae

• Tomato leaf curl geminivirus (ToLCV) requires coat protein (CP) for the accumulation of ssDNA in protoplasts and in plants but not for systemic infection and symptom development in plants [16].

Gene context of Geminiviridae

• Geminivirus VIGS of endogenous genes requires SGS2/SDE1 and SGS3 and defines a new branch in the genetic pathway for silencing in plants [17].
• Effects on geminivirus replication were observed in transgenic plants with altered levels of SUMO, the substrate for UBC9 [18].
• Virus and host-specific adaptations in the BL1 and BR1 genes of bipartite geminiviruses [19].
• Two domains of the AL1 protein mediate geminivirus origin recognition [20].
• Molecular characterization of the AL3 protein encoded by a bipartite geminivirus [21].

Analytical, diagnostic and therapeutic context of Geminiviridae

• Polymerase chain reaction (PCR) was applied to detect and establish provisional identity of begomoviruses through amplification of a approximately 575 bp fragment of the begomoviral coat protein gene (CP), referred to as the 'core' region of the CP gene (core CP) [22].

References