“The very existence of Gene VI has been missed for many years, so we don’t know what implications it might have.
Quote:In spite of the well-documented biological roles of gene VIhttp://www.pnas.org/content/86/23/9203.full.pdf
of the caulimoviruses as a determinant of disease and host
range (7, 9-13), its molecular function is obscure. However,
it is the only viral gene transcribed as a separate transcript
from its own promoter (14, 15). This suggests that gene VI
may have some crucial early role in the infection process,
perhaps as a forerunner of the expression of other viral genes.
In this report, we present evidence that gene VI has such a
role in the posttranscriptional expression of the closely spaced genes of the full-length RNA transcript of FMV.
Quote:RNA silencing is a mechanism for the control of gene expression at the level of RNA abundance (Bartel 2004). It is also an important antiviral defense mechanism in both plants and animals, and therefore most viruses have evolved genes (like Gene VI) that disable it (Dunoyer and Voinnet 2006).
This attribute of Gene VI raises two obvious biosafety concerns: 1) Gene VI will lead to aberrant gene expression in GMO crop plants, with unknown consequences and, 2) Gene VI will interfere with the ability of plants to defend themselves against viral pathogens. There are numerous experiments showing that, in general, viral proteins that disable gene silencing enhance infection by a wide spectrum of viruses (Latham and Wilson 2008).
Gene VI Interferes with Host Defenses