Variable 3’polyadenylation of Wheat yellow mosaic virus and its novel effects on translation and replication

Abstract

Background Polyadenylation influences many aspects of mRNA as well as viral RNA. variable polyadenylation at the 3' end have been reported in RNA viruses. It is interesting to identify the characteristic and potential role of 3' polyadenylation of Wheat yellow mosaic virus (WYMV), which has been reported to contain two genomic RNAs with 3' poly(A) tails and caused severe disease on wheat in East Asia region. Methods 3' RACE was used to identify sequences of the 3′ end in WYMV RNAs from naturally infected wheat by WYMV. In vitro translation assay was performed to analyze effect of UTRs of WYMV with or without 3’polyadenylation on translation. In vitro replication mediated by WYMV NIb protein were performed to evaluate effect of variable polyadenylation on replication. Results Variable polyadenylation in WYMV RNAs was identified via 3′ RACE. WYMV RNAs in naturally infected wheat in China simultaneously present with regions of long, short, or no adenylation at the 3' ends. The effects of variable polyadenylation on translation and replication of WYMV RNAs were evaluated. 5’UTR and 3’UTR of WYMV RNA1 or RNA2 synergistically enhanced the translation of the firefly luciferase ( Fluc ) gene in in vitro WGE system, whereas additional adenylates had an oppositive effect on this enhancement on translation mediated by UTRs of WYMV. Additional adenylates remarkably inhibited the synthesis of complementary strand from viral genome RNA during the in vitro replication mediated by WYMV NIb protein. Conclusions 3' end of WYMV RNAs present variable polyadenylation even no polyadenylation. 3' polyadenylation have opposite effect on translation mediated by UTRs of WYMV RNA1 or RNA2. 3' polyadenylation have negative effect on minus-strand synthesis of WYMV RNA in vitro. Variable polyadenylation of WYMV RNAs may provide sufficient selection on the template for translation and replication. Electronic supplementary material The online version of this article (10.1186/s12985-019-1130-z) contains supplementary material, which is available to authorized users.

Advances in understanding the soil-borne viruses of wheat: from the laboratory bench to strategies for disease control in the field

“…Variable polyadenylation, including the absence of a poly(A) at the 3′-end of WYMV RNAs, was found in different WYMV isolates. The diversity of polyadenylation leads to significant differences in the translation level and minus-strand synthesis of WYMV (Gallie et al 1995;Khan and Goss 2012;Geng et al 2019).…”

“…Variable polyadenylation may play a vital role in template selection for WYMV translation and replication or the molecular transition between WYMV translation and replication (Geng et al 2019). In addition, a new internal ribosome entry site (IRES) was first discovered in the 5′-untranslated region (UTR) of WYMV RNA1, and the dynamic equilibrium state of the tertiary RNA structure was essential for promoting IRES activity in the 5′-UTR of WYMV RNA1.…”

A Novel Plasmid DNA-Based Foot and Mouth Disease Virus Minigenome for Intracytoplasmic mRNA Production

“…The 3 UTR with poly A tail also stabilizes viral RNA and controls the translation process. Moreover, the protein translation activity of each viral 5 UTR appeared to be enhanced by the cognate 3 UTR [17]. Additionally, the length of poly A tail drastically influenced translation efficiency in duck hepatitis A virus type 1 [14].…”

A novel type of IRES having variable numbers of eIF4E-binding site and synergistic effect in RNA2 of WYMV isolates

“…This different evolution pattern may be related with the characteristic of viral proteins encoded by WYMV RNA1 or RNA2. WYMV RNA1 encoded a polyprotein, from which Nib with RNA-dependent RNA polymerase activity was produced and responsible for replication of progeny viralRNAs(Namba et al, 1998;Geng et al, 2019). dsRNA stage during replication of RNA viruses can trigger RNA-induced silencing complex (RISC) of host to cleavag themselves(Zamore et al, 2000).…”