Rigid structural requirement of the 5′ terminus of mRNA for translational activity

Effects of U1 nuclear RNA on translation of messenger RNA

“…as m7GpppAm (IC50 = 60 µ ). This reduction of the inhibition correlates with the decreased translational activity of NAIO4 treated mRNA (Rao et al, 1975;.…”

“…demonstrated that reovirus RNA lacking a methyl group on guanosine bound less efficiently to wheat germ ribosomes. Our studies showed that periodate oxidation of liver mRNA markedly decreased its translational efficiency (Rao et al, 1975;. Hickey et al (1976) observed that addition of 7-methylguanosine S'-phosphate inhibited the translation of capped mRNA but not uncapped mRNA like STNV RNA in the wheat germ system.…”

Effects of Cap Analogue or Cap Removal on the Translation of Rat Brain mRNA In Vitro

“…1975; Held et al, 1977). This was not due to inhibition by periodate (Rao et al, 1975) since, in the method used for oxidation of mRNA, care was taken to remove any contaminating periodate by repeated precipitations of oxidized mRNA with ethanol (Rose and Lodish, 1976). As suggested previously (Rao et al, 1975), it seems reasonable to assume that conversion of ribose cis-diols to dialdehyde by periodate oxidation permits rotation of the 5'-end and leads to the loss of conformational rigidity in the cap, which is supposed to be necessary for forming a stable initiation complex (Adams et al, 1978).…”

“…This was not due to inhibition by periodate (Rao et al, 1975) since, in the method used for oxidation of mRNA, care was taken to remove any contaminating periodate by repeated precipitations of oxidized mRNA with ethanol (Rose and Lodish, 1976). As suggested previously (Rao et al, 1975), it seems reasonable to assume that conversion of ribose cis-diols to dialdehyde by periodate oxidation permits rotation of the 5'-end and leads to the loss of conformational rigidity in the cap, which is supposed to be necessary for forming a stable initiation complex (Adams et al, 1978). Residual messenger activity of p-eliminated mRNA The residual protein synthesis by &eliminated mRNA could be interpreted as being due to a partial recapping of mRNA by guanyltransferase and guanylmethylase presumably present in the extract or to a small part of the mRNA molecules that had escaped oxidation and p-elimination.…”

“…This technique has so far been successfully used for viral mRNAs only. For cellular mRNA, the 5'-terminal nucleoside is modified or entirely removed by periodate oxidation followed by P-elimination of the nucleoside dialdehyde (Rao et al, 1975;Muthukrishnan et al, 197%;Lodish and Rose, 1977). To avoid degradation and secondary effects of chemical treatments, mRNAs have also been treated with cap-removing enzymes (Abraham and Pihl, 1977;Efstratiadis et al, 1977;Zan-Kowalczewka et al, 1977).…”