3 research outputs found
Lipid Composition of the Viral Envelope of Three Strains of Influenza VirusNot All Viruses Are Created Equal
Although
differences in the rate of virus fusion and budding from the host
cell membrane have been correlated with pathogenicity, no systematic
study of the contribution of differences in viral envelope composition
has previously been attempted. Using rigorous virus purification,
marked differences between virions and host were observed. Over 125
phospholipid species have been quantitated for three strains of influenza
(HKx31-H3N2, PR8-H1N1, and VN1203-H5N1) grown in eggs. The glycerophospholipid
composition of purified virions differs from that of the host or that
of typical mammalian cells. Phosphatidylcholine is the major component
in most mammalian cell membranes, whereas in purified virions phosphatidylethanolamine
dominates. Due to its effects on membrane curvature, it is likely
that the variations in its content are important to viral processing
during infection. This integrated method of virion isolation with
systematic analysis of glycerophospholipids provides a tool for the
assessment of species-specific biomarkers of viral pathogenicity
Lipid Composition of the Viral Envelope of Three Strains of Influenza VirusNot All Viruses Are Created Equal
Although
differences in the rate of virus fusion and budding from the host
cell membrane have been correlated with pathogenicity, no systematic
study of the contribution of differences in viral envelope composition
has previously been attempted. Using rigorous virus purification,
marked differences between virions and host were observed. Over 125
phospholipid species have been quantitated for three strains of influenza
(HKx31-H3N2, PR8-H1N1, and VN1203-H5N1) grown in eggs. The glycerophospholipid
composition of purified virions differs from that of the host or that
of typical mammalian cells. Phosphatidylcholine is the major component
in most mammalian cell membranes, whereas in purified virions phosphatidylethanolamine
dominates. Due to its effects on membrane curvature, it is likely
that the variations in its content are important to viral processing
during infection. This integrated method of virion isolation with
systematic analysis of glycerophospholipids provides a tool for the
assessment of species-specific biomarkers of viral pathogenicity
Diacylglycerol Kinase Delta Promotes Lipogenesis
We
have studied the relationship between diacylglycerol kinase delta
(DGKδ) and lipogenesis. There is a marked increase in the expression
of DGKδ during the differentiation of 3T3-L1 cells to adipocytes,
as well as in the synthesis of neutral and polar lipids. When 3T3-L1
undifferentiated fibroblasts are transfected to express DGKδ,
there is increased triglyceride synthesis without differentiation
to adipocytes. Hence, expression of DGKδ promotes lipogenesis.
Lipid synthesis is decreased in DGKδ knockout mouse embryo fibroblasts,
especially for lipids with shorter acyl chains and limited unsaturation.
This reduction occurs for both neutral and polar lipids. These findings
suggest reduced <i>de novo</i> lipid synthesis. This is
confirmed by measuring the incorporation of glycerol into polar and
neutral lipids, which is higher in the wild type cells than in the
DGKδ knockouts. In comparison, there was no change in lipid
synthesis in DGKε knockout mouse embryo fibroblasts. We also
demonstrate that the DGKδ knockout cells had a lower expression
of acetyl-CoA carboxylase and fatty acid synthase as well as a lower
degree of activation by phosphorylation of ATP citrate lyase. These
three enzymes are involved in the synthesis of long chain fatty acids.
Our results demonstrate that DGKδ markedly increases lipid synthesis,
at least in part as a result of promoting the <i>de novo</i> synthesis of fatty acids