In this article we will discuss about the processing of rRNA in prokaryotes (e.g. E. coli) and eukaryotes (e.g. mammals). In prokaryotes (e.g. E. coli) there are seven operons for rRNA. These are dispersed throughout the genome. Each operon consists of one copy of each of the 5S, 16S and 23S rRNA sequences. Coding sequences for tRNA molecules are present [...]
The following points highlight the four types of RNA. The types are: 1. Ribosomal RNA 2. Transfer RNA 3. Messenger RNA 4. Genetic RNA. Type # 1. Ribosomal RNA (rRNA): It is the most abundant RNA (70-80% of total) which has 3-4 types. Some of its types (23S, 28S) are the longest of all RNAs. As the name indicates, rRNA [...]
In this article we will discuss about the maturation of mRNA from HnRNA. In higher organisms, within the nucleus, heterogenous nuclear RNA (HnRNA) or high molecular weight RNA (HMW RNA) or DNA-like-RNA (dRNA) is synthesized. These molecules are larger than mRNA and used in cytoplasm. Polymerase-I is added at 3'-end of HnRNA. Subsequently mRNA molecule is released when HnRNA having [...]