Discontinuous translation and mRNA structure of the coding region.

An analysis of the published data of the electrophoresis of the products of silk fibroin exhibiting discontinuities or pauses in the translational process showed that about 60 times of pauses occur during the translation of the mRNA from silk fibroin. In addition, we estimated that silk fibroin gene as a whole (15 kb) is composed of about 60 alternate, crystalline-noncrystalline, arrays of nucleotide sequence elements each connected by the boundary sequence, on the basis of the nucleotide sequence of the partial cDNA clone of the heavy chain gene of Bombyx mori available in the literature. The coincidence of the total number of pauses with that of the alternate arrays suggests that one translational pausing site exists in each of the unit (alternate array + boundary) nucleotide sequence in the silk fibroin mRNA template.