Multi‐tasking of nonstructural gene products is required for bean yellow dwarf geminivirus transcriptional regulation

Abstract

Geminiviruses belong to a family of plant viruses that can be classified into four distinct genera on the basis of genomic organization, vector transmissibility and host range. These include the mastreviruses, which possess monopartite genomes, are transmitted by leafhoppers and infect monocotyledonous plants. Exceptions to the rule are the Australian-derived tobacco yellow dwarf virus and South African-derived bean yellow dwarf virus (BeYDV), two distantly related mastreviruses that infect dicotyledenous plants [1].BeYDV consists of a single-stranded circular DNA molecule of 2.6 kb in length, and contains four ORFs encoding three different genes. The coding region is divided bidirectionally by long intergenic regions (LIR) and short intergenic regions (SIR). The MP and CP genes are expressed from the virion sensestrand, while the replication-associated protein (Rep) is produced from overlapping ORFs C1 and C2 from the complementary sense-strand. An intron spans the region overlapping C1 and C2 and this is spliced during Rep expression. Both Rep, which functions as the replication-associated protein, and RepA, the gene product of ORF C1, are produced during virus infection [1][2][3].

DNA Replicons for Plant Genome Engineering

“…We chose to position heterologous sequence downstream of the LIR in the virion-sense direction. The LIR functions as a bidirectional promoter and promoter strength in the virion-sense direction is weak in the absence of Rep and RepA proteins (Hefferon et al, 2006). To promote high gene expression within circularized GVRs, we positioned a duplicated 35S promoter (P35S) upstream of the LIR in the virion-sense direction.…”

“…Splice donor and acceptor sequences were positioned upstream and downstream, respectively, of the LIR sequence that is predicted to form after circularization. High-protein expression may also occur from the transactivation of the virion-sense LIR promoter by the viral Rep proteins (Hefferon et al, 2006).…”

Recombination hotspots and host susceptibility modulate the adaptive value of recombination during maize streak virus evolution

“…MSV-A is distributed throughout sub-Saharan Africa where it jeopardizes sustainable maize production in some of the world's poorest countries [19-21]. Its single component, circular, ~2.7 Kb, single-stranded DNA (ssDNA) genome encodes a movement protein (MP) and coat protein (CP) in the virion-sense [22-24], and in the complementary-sense the replication-associated proteins Rep and RepA [25-29]. Separating the virion- and complementary-sense open reading frames (ORFs) are the long intergenic region (LIR) - comprising transcriptional promoter elements and the virion strand origin of replication ( v-ori ) [30] - and a short intergenic region (SIR), where the transcription termination elements and the complementary strand origin of replication reside.…”

First genome analysis and molecular characterization of Chickpea chlorotic dwarf virus Egyptian isolate infecting squash

“…The virion-sense expression comes out with the movement protein (MP) and a coat protein (Cp), and the complementary-sense expression of the replication-associated proteins, Rep and RepA. Whereas the MP and Cp are involved in virus movement and encapsidation [25], Rep is an crucial initiator of virus replication, and RepA plays regulatory role of host and viral gene transcription [15,16]. Masterviruses family adopts host DNA replication and double-stranded DNA break repair proteins in their genome replication via rolling-circle mechanism [2] and recombination-dependent mechanism [8].…”