Messenger RNA transcription

Messenger RNA transcripts of protein-coding genes in prokaryotes require little or no modification before translation. Ribosomal RNAs and transfer RNAs are synthesized as precursor molecules that require processing by specific ribonucleases to release the mature RNA molecules. 

In several studies designed to examine the pattern of delta opioid receptor expression in the gut, messenger RNA transcripts encoding the delta opioid... 

Coventry BJ, Weeks SC, Heckford SE, et al. Lack of IL-2 cytokine expression despite 11-2 messenger RNA transcription in tumor-infiltrating lymphocytes in primary human breast carcinoma selective expression of early activation markers. J Immunol 1996 156 3486-92. 

It is clear that most, if not all, neuropeptides are derived from larger precursor proteins, which are translations of messenger RNA transcripts of specific genes. In many cases it appears that the precursor protein contains... 

Transcription and translation are coupled in the cytoplasm of prokaryotes. In eukaryotes, transcription of DNA and subsequent processsing of the messenger RNA transcript both occur in the nucleus, while translation of the mature mRNA template occurs in the cytoplasm. Cell-free systems lack mechanisms for mRNA processing, and therefore require fully matured... 

SOD-mimetic activity of Cu(II)(3,5-DIPS)2 also led to studies of this compound s ability to inhibit interleukin-2 (IL-2) synthesis by a mouse thymoma cell line, EL4 [379]. Cu(IIX3,5-DIPS)2 did inhibit phorbol diester-induced synthesis of IL-2 (IC50 = 10 /xM), but it did not inhibit phorbol-diester-induc-ed attachment of these cells to substrate. While 3,5-DIPS also inhibited IL-2 synthesis (IC50 value = 15 /xM), CUCI2 was ineffective (100 /xM). Mechanistically, the inhibition of IL-2 synthesis by Cu(IIX3,5-DIPS)2 was suggested to be due to an inhibition of IL-2 messenger RNA transcription [379]. 

Section 28 11 Three RNAs are involved m gene expression In the transcription phase a strand of messenger RNA (mRNA) is synthesized from a DNA tern plate The four bases A G C and U taken three at a time generate 64 possible combinations called codons These 64 codons comprise the genetic code and code for the 20 ammo acids found m proteins plus start and stop signals The mRNA sequence is translated into a prescribed protein sequence at the ribosomes There small polynucleotides called... 

If an antibody to the protein of interest is available, it is sometimes possible to use vector sequences, eg, the beta-galactosidase promoter sequence, to direct the transcription of the passenger DNA into messenger RNA and the translation of that mRNA into protein which can be recognized by the antibody. Although this method is somewhat less reHable than the use of nucleic acid probes, specialized vectors are available for this purpose. 

Messenger RNA (Section 28.4) A kind of RNA formed by transcription of DNA and used to carry genetic messages from DNA to ribosomes. 

Messenger RNA (mRNA) is the intermediate template between DNA and proteins. The information from a particular gene is transferred from a strand of DNA by the construction of a complementary strand of RNA through a process known as transcription. The amount of any particular type of mRNA in a cell reflects the extent to which a gene has been expressed . 

Reverse transcription is the copying of an RNA molecule back into its DNA complement. The enzymes that perform this function are called reverse transcriptases. Reverse transcription is used naturally by retroviruses to insert themselves into an organism s genome. Artificially induced reverse transcription is a useful technique for translating unstable messenger RNA (mRNA) molecules into stable cDNA. 

Some RNA molecules have intrinsic catalytic activity. The activity of these ribozymes often involves the cleavage of a nucleic acid. An example is the role of RNA in catalyzing the processing of the primary transcript of a gene into mature messenger RNA. 

Bacteria, being procaryotic, do not show compartmentation of the biosynthetic processes. The genome of a bacterium relates directly to the cytoplasm of the cell. Transcription into mRNA can lead directly to translation, and the processes of transcription and translation are not carried out in separate organelles. Animal cells, being eucaryotic, show compartmentation of the transcription and translation processes. Transcription of the genome into mRNA occurs in the nucleus, whereas translation occurs in the cytoplasm. The messenger RNA in the eucaryote is usually modified by adding to it... 

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