Is more ‘A’ better?

12 Nov 15 NUS scientists discovered that Hibiscus latent Singapore virus with a longer internal poly(A) tract replicates faster.

Hibiscus latent Singapore virus (HLSV) is a plant virus (see Figure) that shares its genetic makeups with the famous Tobacco mosaic virus which has been studied for over 100 years. A team led by Prof WONG Sek Man from the Department of Biological Sciences in NUS discovered that the significance of this research is that now they have a better understanding of the genetic variations in the plant virus world. Generally the virus replicates more efficiently with a longer internal string of Adenines (A) tract. Adenine is one of the fundamental components of nucleic acids. The normal length of As in the virus is about 80.Shortening of the string of As will slow down the virus replication.

By knowing the importance of the length of the internal string of As, it facilitates the design in viral vectors for protein expression. They can use HLSV and modify the genetic makeup so that it can be used to express a protein of interest, for example, a short analgesic peptide that relieves pain. They will take into consideration the proper length of the string of As when we generate a viral vector using HLSV.

The next step of this research is to test if they can replace the internal string of As with other nucleotides? This will allows them to understand how did HLSV acquire such genetic component and whether such a process is universal in the plant virus world? If so, what is the molecular mechanism behind the observed phenomenon?

WongSM Nov 

Figure shows the Hibiscus latent Singapore virus induces yellow spots on Chenopodium quinoa L. leaf. [Image credit: Wong SM]


1. Niu S, Cao S, Huang LJ, Tan KCL, Wong SM. “The length of an internal poly(A) tract of Hibiscus latent Singapore virus is crucial for its replication.” Virology 474 (2015) 52.

2. Niu SN, Cao SS, Wong SM. ”An infectious RNA with a hepta-adenosine stretch responsible for programmed -1 ribosomal frameshift derived from a full-length cDNA clone of Hibiscus latent Singapore virus.” Virology 449 (2014) 229.