Regulation of transcription

Template availability Methylation Exposure of DNA Attraction for RNA polymerase Promoter TATA, CAT Transcription factors Alternative Poly(A) tailing Alternative splicing Alternative translation start 

As goes RNA, so goes protein. Higher levels of mRNA are associated with higher levels of the encoded protein. There is a definite need to regulate the amounts of different proteins during development, differ- 

Eukaryotes have a specific signal for termination of transcription however, prokaryotes seem to have lost this mechanism. Once started, RNA polymerase keeps going, making a primary transcript [pre-mRNA or hnRNA (for heterogeneous nuclear)] until far past the end of the final mRNA message. 

The above points will be discussed in more detail in the following section (1.4) in the context of eucaryotic gene regulation. 

Only autoregulation will be introduced as an example for the regulation of DNA-brndrng proteins at the level of transcription. 

An example for autoregulation is found in the hut-operon of E. coli and in the regulation of the SOS response in bacteria via the lex A repressor. There are examples of autoregulation at the level of translation as well (see 1.5.6). 

With the aid of autoregulatory processes it is possible for the cell to maintain a minimal concentration of repressor. 

Procaryotes and eucaryotes differ decisively in the structure of the transcription start site and the complexity of the transcription appartus. For a better understanding we want to briefly summarize procaryotic transcription and then contrast it to eucaryotic transcription (review Eick and Heumarm, 1994). 

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Apoptotic executioner caspases (caspase-3, -6, -7) constitute a subgroup of the caspase family. These proteases are the workhorses of the apoptotic process as they are responsible for cleaving many down-stream substrates important for cellular morphology, organelle homeostasis, cell cycle arrest, and regulation of transcription and translation. 

Treisman, R., Regulation of transcription by MAP kinase cascades, Curr. Opin. Cell. Biol., 8, 205-215, 1996. 

Khan AU, Krishnamurthy S (2005) Histone modifications as key regulators of transcription. Front Biosci 10 866-872... 

Co regulators of transcription — histone acetylases modulate chromatin structure 461... 

The mechanisms of corticosteroid receptor regulation of transcription have been elucidated 464... 

The mechanisms of corticosteroid receptor regulation of transcription have been elucidated. Both type I and type II corticosteroid receptors are members of a superfamily of ligand-activated transcription factors defined by protein sequence similarity. Included in this superfamily are various other steroid receptors, such as the estrogen receptor, as well as members of the retinoic acid receptor... 

The regulation of transcription by hormones requires a controlled limitation in order to guarantee that the protein is produced in adequate amounts. This process, nevertheless, is very poorly understood for members of the family of nuclear receptors. 

Vandromme, M., Gauthier-Rouviere, C., Lamb, N., and Fernandez, A. (1996). Regulation of transcription factor localization fine-tuning of gene expression. Trends Biochem. 

Chen D, Ma H, Hong H, Koh SS, Huang SM, Schurter BT, Aswad DW, Stallcup MR (1999) Regulation of transcription by a protein methyltransferase. Science 284 2174-2177 Chubb JR, Boyle S, Perry P, Bickmore WA (2002) Chromatin motion is constrained by association with nuclear compartments in human cells. Curr Biol 12 439-445 Croston GE, Kadonaga JT (1993) Role of chromatin structure in the regulation of transcription by RNA polymerase II. Curr Opin Cell Biol 5 417-423... 

Nucleolin has also been implicated in the regulation of transcription of the Krtippel-like Factor 2 (KLF2) transcription factor. KLF2 is required for developmental and cellular functions in several distinct tissue types. Its transcription... 

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