Posttranscriptional Regulation in Adenovirus Infected Cells

A deeper
understanding of how viruses reprogram their hosts for production
of progeny is needed to combat infections. Most knowledge on the regulation
of cellular gene expression during adenovirus infection is derived
from mRNA studies. Here, we investigated the changes in protein expression
during the late phase of adenovirus type 2 (Ad2) infection of the
IMR-90 cell line by stable isotope labeling in cell culture with subsequent
liquid chromatography–high resolution tandem mass spectrometric
analysis. Two biological replicates of samples collected at 24 and
36 h post-infection (hpi) were investigated using swapped labeling.
In total, 2648 and 2394 proteins were quantified at 24 and 36 hpi,
respectively. Among them, 659 and 645 were deregulated >1.6-fold
at the two time points. The protein expression was compared with RNA
expression using cDNA sequencing data. The correlation was surprisingly
low (r = 0.3), and several examples of posttranscriptional
regulation were observed; e.g., proteins related to carbohydrate metabolism
were up-regulated at the protein level but unchanged at the RNA level,
whereas histone proteins were down-regulated at the protein level
but up-regulated at the RNA level. The deregulation of cellular gene
expression by adenovirus is mediated at multiple levels and more complex
than hitherto believed.