Science, People & Politics issn:1751598x. Iss. one 2017

ZIKA VIRUS FEATURE | 19

Li et al write,

"Given the number of host cells and viral variants [of Zika], it has been difficult to identify the
pathogenic factors and to generate a consensus on ZIKV [Zika virus] protein functionality."

This was the research team's starting point.

As with HIV in the febrile research days of the early 1980s surrounding identification of its role
in AIDS, Zika and its pathology are poorly understood. Then Robert Gallo and others clashed
via publications in high-impact international scientific journals as they raced - literally - to under-
stand AIDS and its causes.

Since then biomedical research techniques have undergone revolution after revolution. Each
year billions and billions of dollars are spent on biomedical research, and that is in the US
alone. In the January, 2017 PNAS paper by Li et al, which Gallo contributed to PNAS, Li et al
deployed many techniques honed in recent decades including: plasmids, clones, shotgun
cloning, vectors, RT-PCR, post-genomic analyses, transfection, green-fluorescent proteins
(GFP) bonded to the protein of interest etc...

LI et al TAKE ON ZIKA
What follows is what Li et al did, what they found out, and their informed view that their findings
can leverage future Zika research.

First, they selected S. Pombe because it has critical biological attributes akin to human cell
biology, as well as biological pathways for a number of functions which are similar in mammals.
That is, S. Pombe is a so-called model organism. While no model organism can be an exact
surrogate for a human or some other species' biology, in the circumstances of this research
S. Pombe ticked relevant boxes.

Working with old and new techniques, the researchers explored cell pathology resulting from
Zika infection. They experimented on whole S.Pombe cells, alone and in colonies. One strain
was a wild type, another way of describing naturally occurring organisms. Two others were
mutant strains selected for the metabolic path they influence, which made them useful for
probing one aspect of cytopathology in Zika-infected host cells. Agents (plasmids and vectors)
carrying just the genetic material needed to express the proteins they wanted to observe in the
host system were recruited.

Having decided which surrogate organism to work with, Li et al localised Zika's proteins in
S. Pombe cells. Zika codes for 14 proteins. To visualise locale they fused the genetic code for
green florescent protein (GFP) with that of each viral protein. The whole was placed in a gene
expression vector, and the vector carried the protein-expressing genes into wild type S. Pombe.
Fluorescent microscopy identified where the 14 proteins positioned themselves in the cell.

Though Zika viral proteins located themselves in S. Pombe in the position one would expect,

Continued on page 21 | 19

Issue 1 (Jan-Mar), 2017............................................Science, People & Politics ISSN 1751-598X print and online