Polyamine enhancement of the synthesis of adenylate cyclase at the translational level and the consequential stimulation of the synthesis of the RNA polymerase sigma(28) subunit
M. Yoshida et al., Polyamine enhancement of the synthesis of adenylate cyclase at the translational level and the consequential stimulation of the synthesis of the RNA polymerase sigma(28) subunit, J BIOL CHEM, 276(19), 2001, pp. 16289-16295
The effects of polyamines on the synthesis of various a subunits of RNA pol
ymerase were studied using Western blot analysis. Synthesis of sigma (28) w
as stimulated 4.0-fold and that of sigma (38) was stimulated 2.3-fold by po
lyamines, whereas synthesis of other a subunits was not influenced by polya
mines. Stimulation of sigma (28) synthesis was due to an increase in the le
vel of cAMP, which occurred through polyamine stimulation of the synthesis
of adenylate cyclase at the level of translation. Polyamines were found to
increase the translation of adenylate cyclase mRNA by facilitating the UUG
codon-dependent initiation. Analysis of RNA secondary structure suggests th
at exposure of the Shine-Dalgarno sequence of mRNA is a prerequisite for po
lyamine stimulation of the UUG codon-dependent initiation.