7-methylguanosine-triphosphate and 7-methylguanosine-5--monophosphate

This article describes a simple, reliable, efficient, and general method for the synthesis of 7-methylguanosine nucleotides such as 7-methylguanosine 5'-O-monophosphate (m

Topics: Guanosine Diphosphate; Indicators and Reagents; Methylation; RNA Cap Analogs; Solvents; Sulfuric Acid Esters

An enzyme-linked immunosorbent assay was utilized for the detection of spontaneously occurring antibodies with apparent specificities for m7G, 5'-m7GMP, and m7G(5')ppp(5')C. From the sera of 50 patients containing anti-nuclear antibodies, 48 (96%) possessed antibodies which bound to one or more immobilized nucleoside-BSA antigens (A-, G-, C-, U-, and T-BSA). Additionally, 8 (16%) of these sera contained immunoglobulins that reacted with m7G-BSA antigen. In these latter sera, soluble competitors such as m7G, 5'm7GMP, and m7G(5')ppp(5')C (but not 5'-AMP, -GMP, -CMP, -UMP, and -TMP or m1G and m22G) effectively inhibited antibody-binding to immobilized m7G-BSA. These results indicate the existence of spontaneously occurring anti-m7G antibodies in autoimmune diseases which are distinct from anti-G antibody populations.

Topics: Antibodies, Antinuclear; Autoantibodies; Binding, Competitive; Enzyme-Linked Immunosorbent Assay; Guanine Nucleotides; Humans; RNA Cap Analogs; RNA Caps; Serum Albumin, Bovine

The cap analogues 7-methylguanosine 5'-phosphate [m7G(5')p], 7-methylguanosine 5'-triphosphate [m7G(5')ppp] and 2'-O-methylguanosine 5'-triphosphate [Gm(5')ppp] inhibit the translation of capped globin mRNA and encephalomyocarditis (EMC) RNA (a naturally uncapped mRNA) in a reticulocyte cell-free system. This inhibition occurs at the level of protein synthesis initiation and is of a competitive type since it can be overcome by increasing the mRNA concentration. However, the translation of globin mRNA is more sensitive to the inhibitory effects of the cap analogues m7G(5')p and m7G(5')ppp than translation of EMC RNA. The same spectra of specific inhibition is also observed with some other initiation inhibitors such as aurintricarboxylic acid, which inhibits mRNA binding, but not with pactamycin which does not affect mRNA interaction. A model is presented suggesting that this preferential inhibition by cap analogues could be explained mainly by the different affinities of globin mRNA and EMC RNA for the initiation complexes between 40-S subunits and Met-tRNAf. Moreover Gm(5')ppp cannot be considered simply as a cap analogue since it also affects some step prior to mRNA binding.

Topics: Animals; Encephalomyocarditis virus; Globins; Kinetics; Peptide Initiation Factors; Protein Biosynthesis; Rabbits; Reticulocytes; RNA Cap Analogs; RNA Caps; RNA, Messenger