Non-coordinate synthesis and methylation of tRNA following excision of plant tissue

Abstract

The relationship between the synthesis and methylation of nucleic acids in tissue slices from higher plant storage organs has been investigated. Although the observed nucleic acid synthesis is mainly an expression of rRNA synthesis the highest level of methylation occurs in tRNA. Unlike the synthesis and methylation of rRNA which appears completely coupled, the methylation of tRNA is not tightly coupled to its synthesis. It is suggested that a pool of undermethylated tRNA exists in the tissue prior to incubation and that methylation of this tRNA initially controls the rate of protein synthesis in the tissue slices.

Some uses of tissue expiants in the teaching of protein synthesis

“…These changes are thought to be part of a completely new developmental sequence which, given the correct conditions, can lead to cell division. Studies of the nucleic acid metabolism during this period (King and Chapman, 1973) indicate that the factors which control this new developmental sequence have definite similarities to those factors operating in other more clearly defined differentiating tissues, for example in slime mould morpho genesis and sea urchin embryogenesis. Certain of the fundamental biochemical changes observed in tissue expiants are relatively easy for students to follow, and offer a basis for experiments which illustrate some of the techniques and reasoning encountered in more sophisticated investigations.…”