Amino acid deficiency up-regulates
specific mRNAs in murine embryonic cells.
J Nutr. 2002 Aug;132(8):2137-42
Fontanier-Razzaq N, Harries DN, Hay SM, Rees WD.
The flow of amino acids to both protein and DNA synthesis
is particularly important during periods of rapid cell proliferation
such as the fetal stages of life. The changes in mRNA levels
caused by the different types of growth arrest were studied
in F9 embryonal carcinoma cells. The cells were grown in
medium deficient in the amino acid lysine or in one containing
phosphonoacetyl L-aspartic acid (PALA), which inhibits the
incorporation of aspartic acid into pyrimidine nucleotides.
A number of mRNAs known to be elevated in growth arrested
cells (gas and gadd) were studied by Northern blotting. Samples
of RNA from the cells were also compared by differential
display reverse transcription-polymerase chain reaction (DDRT-PCR).
The results showed that lysine deficiency increased the steady-state
levels of a number of mRNAs by 5- to 40-fold. In contrast,
the changes in cells treated with PALA were much smaller
and less pronounced. Amino acid deficiency induced the mRNAs
coding for gadd153 (CHOP-10), gas5, the mouse doublesex-related
gene (Dmrt1) and the polyamine modulated factor (PA-1) as
well as a number of unidentified expressed sequence tags
(EST). These mRNAs were all induced within 24 h of exposure
to amino acid deficiency. These very different transcriptional
responses may be important in understanding the interactions
between protein quantity and quality in different physiologic
situations. |