Information Technology Reference
In-Depth Information
RNA molecules (in the many different forms, such as pre-mRNA, mRNA,
snRNA, snoRNA, miRNA, lincRNA, siRNA, tRNR, rRNA, shRNA, and ribo-
switches) play crucial roles (often in molecular complexes with proteins) in the
all the phases of the whole process of transcription/translation, which consists of a
cycle (DNA
→
→
→
DNA).
In the phase preceding the translation, other mechanisms of
post-transcriptional
modification may intervene that alter the mRNA in order to modulate or even block
the normal translation (see, for example, Sect. 4.5). Analogously, even when the
translation is realized,
post-translational
modification may further modulate the
overall result of the long way from genes to proteins. The richness and flexibility of
these collateral processes is probably the key to the role of
epigenetics
, concerning
the processes that have no direct record in the genes, but modulate gene expres-
sion in correspondence to the different contexts of their realization, and moreover
can acquire certain forms of biologic memory, with possible short-term hereditable
characters.
RNA
Proteins
Fig. 4.4
From a gene to a protein via transcription, splicing, and translation
