Transcripts gene expression

Wilson KF. Signal transduction and post-transcriptional gene expression. Biol Chem 2000 381 357-365. 

The mechanical properties of DNA have attracted the interest of both physicists and biologists because of their relation to many biological events such as DNA transcription, gene expression and regulation, and DNA rephcation. 

Luthi-Carter R et al (2002) Polyglutamine and transcription gene expression changes shared by DRPLA and Huntington s disease mouse models reveal context-independent effects. Hum Mol Genet 11(17) 1927-1937... 

The structure of the DNA molecule is intimately related to its two primary roles replication (gene duplication by synthesis of more DNA) and transcription (gene expression by synthesis ofRNA) (see Fig. 4.1). 

Transcription First step in gene expression, corresponding to the generation of mRNA from the original DNA... 

Genes are DNA and carry the inheritable characteristics of an organism and these characteristics are normally expressed at the molecular level via protein synthesis Gene expression consists of two stages transcription and translation, both of which involve RNAs Sections 28 11 and 28 12 describe these RNAs and their roles m transcription and translation... 

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... 

Eucaryotes have many more genes and a broader range of specific transcription factors than procaryotes and gene expression is regulated by using sets of these factors in a combinatorial way. Eucaryotes have found several different solutions to the problem of producing a three-dimensional scaffold that allows a protein to interact specifically with DNA. In the next chapter we shall discuss some of the solutions that have no counterpart in procaryotes. However, the procaryotic helix-turn-helix solution to this problem (see Chapter 8) is also exploited in eucaryotes, in homeodomain proteins and some other families of transcription factors. 

Antisense therapy means the selective, sequence-specific inhibition of gene expression by single-stranded DNA oligonucleotides. By hybridizing to the target mRNA, which results in a subsequent double-helix formation, gene expression is blocked. This process can occur at any point between the conclusion of transcription and initiation of translation or even possibly during translation. 

In higher eukaiyotes, most of the chromosomal DNA carries 5-methyl-cytidine residues located in CpG sequence motives. There is a close correlation between transcriptional inactivation and methylation. On the other hand, considerable evidence shows that regions of DNA that are actively engaged in transcription lack 5-methyl-cytidine nucleotides in CpG motivs. Hence DNA methylation is a means how cells regulate gene expression. DNA methylation which is catalyzed by DNA methyltransferases is the best characterized epigenetic mechanism. 

In the context of gene expression analysis, gene products include proximal products, such as primary transcripts, intermediate products, such as mRNA, tRNA, and rRNA, and distal products including proteins and peptides. 

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