MRNA coding regions

Translation The stepwise synthesis of a polypeptide with an amino acid sequence determined by the nucleotide sequence of the mRNA coding region. The genetic code relates each amino acid to a group of three... 

Dias N., Dheur S., Nielsen P.E., Gryaznov S., Van Aerschot A., Herde-wijN P., Helene G., Saison-Behmoaras T. E. Antisense PNA tridecamers targeted to the coding region of Ha-ras mRNA arrest polypeptide chain elongation. J. Mol. Biol. 1999 294 403-416. 

In contrast to most mRNAs, which become untranslatable after a temperature downshock, cold shock mRNAs possess a mechanism to form the translation initiation complex at low temperature without cold shock ribosomes. A close inspection of the mRNAs of class I cold shock proteins reveal that they are equipped with an extra ribosome-binding site called the downstream box located within the coding region of their transcript [130]. It would be interesting to know whether introduction of this downstream box into a cellular mRNA would convert it into a transcript which can be transcribed immediately after a cold shock. In the case of the cspA mRNA it has been shown that in the absence of the downstream box the initiation complex cannot be formed at low temperature during the accHmation phase [131]. 

The protein coding regions of DNA, the transcripts of which ultimately appear in the cytoplasm as single mRNA molecules, are usually interrupted in the eukaryotic genome by large intervening sequences of... 

Figure 39-19. Structure of a typical eukaryotic mRNA showing elements that are involved in regulating mRNA stability. The typical eukaryotic mRNA has a 5 noncoding sequence (5 NCS), a coding region, and a 3 NCS. All are capped at the 5 end, and most have a polyadenylate sequence at the 3 end. The 5 cap and 3 poly(A) tail protect the mRNA against exonuclease attack. Stem-loop structures in the 5 and 3 NCS, features in the coding sequence, and the AU-rich region in the 3 NCS are thought to play roles in mRNA stability.

Lin X, Parsels LA, Voeller DM et al. Characterization of a cis-acting regulatory element in the protein coding region of thymidylate synthase mRNA. Nucleic Acids Res 2000 28 1381-1389. 

The product inhibits replication of human CMV (HCMV) via an antisense mechanism. Its nucleotide sequence is complementary to a sequence in mRNA transcripts of the major immediate early region (IE2 region) of HCMV. These mRNAs code for several essential viral proteins and blocking their synthesis effectively inhibits viral replication. 

Translation of Viral mRNA. Once viral mRNA has been formed, translation occurs in the host cytoplasm, using host ribosome to synthesize viral proteins. Viral mRNA, which is usually monocistronic (i.e., has a single coding region) can displace host mRNA from ribosome so that viral products are synthesized preferentially. In the early phase, the proteins produced (enzymes, regulatory molecules) are those that will allow subsequent replication of viral nucleic acids in the later phase, the proteins necessary for the formation of capsid are produced. 

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