Disease relevance of Rep

• Identification of Rep as resembling the family of ribonucleoprotein/RNA-recognition motif fold proteins establishes a structure-based evolutionary link between RNA binding proteins, splicing factors, and replication initiators of prokaryotic and eukaryotic single-stranded DNA elements and mammalian DNA tumor viruses [1].
• The origin of replication of African cassava mosaic virus (ACMV) and a gene expression vector based on Potato virus X were exploited to devise an in planta system for functional analysis of the geminivirus replication-associated protein (Rep) in transgenic Nicotiana benthamiana line pOri-2 [2].
• These results prompt a reassessment of the current model of geminivirus replication where Rep/DNA interaction is a highly specific step in the initiation of rolling circle replication [3].

High impact information on Rep

• Here we present the solution NMR structure of the catalytic domain of Rep, the initiator protein of tomato yellow leaf curl virus [1].
• The release of episomal trans replicons from the transgene and the increase in GFP expression were dependent on the cognate geminiviral replication-associated protein (Rep) and required interaction between Rep and the intergenic region of TYLCSV [4].
• This line contains an integrated copy of a tandem repeat of the ACMV origin of replication flanking nonviral sequences that can be mobilized and replicated by Rep as an episomal replicon [2].
• We have used a combination of protein-binding assays and mutagenesis to show that repeat motifs in TLCV and sat-DNA are essential for Rep-binding in vitro [3].
• The DNA binding sites for the replication-associated protein (Rep) of two strains of tomato leaf curl virus from New Delhi (ToLCV-Nde) were identified using electrophoretic mobility shift assays (EMSAs) [5].

Biological context of Rep

• A Rep-GFP fusion protein can also mobilize and amplify the replicon, facilitating Rep detection in planta [2].

References