Gene transcriptions/Promoters/Proximals

The proximal sequence upstream of the gene that tends to contain primary regulatory elements is a proximal promoter.

It is approximately 250 base pairs or nucleotides, nts upstream of the transcription start site.

Genetics edit

Def. "[a] unit of heredity; a segment of DNA or RNA that is transmitted from one generation to the next, and that carries genetic information such as the sequence of amino acids for a protein"[1] is called a gene.

The genetic information in a genome is held within genes, and the complete set of this information in an organism is called its genotype. A gene is a unit of heredity and is a region of DNA that influences a particular characteristic in an organism. Genes contain an open reading frame that can be transcribed, as well as regulatory sequences such as promoters and enhancers, which control the transcription of the open reading frame.

Promoters edit

Def. a "section of DNA that controls the initiation of RNA transcription as a product of a gene"[2] is called a promoter.

Proximus edit

Def. "neighbour, nearest person or thing"[3] is called proximus.

Theoretical proximal promoters edit

Def. a "promoter region [juxtaposed to the core promoter that] binds transcription factors that modify the affinity of the core promoter for RNA polymerase.[12][13]"[4] is called a proximal promoter.

Distal promoters edit

A distal promoter is a distant (in numbers of nucleotides) portion of the promoter for a particular gene.

This distal sequence is upstream of the gene.

It is a region of DNA that may contain additional regulatory elements, often with a weaker influence than the proximal promoter.

Dispersed promoters edit

A dispersed promoter is a region of DNA that facilitates the transcription of a particular gene, where this promoter region contains several transcription start sites over 50-100 nucleotides.

Dispersed promoters are more recent and less widespread throughout nature than focused promoters.[5]

Focused promoters edit

A focused promoter contains either a single transcription start site or a distinct cluster of start sites over several nucleotides.[5] Focused promoters are sometimes referred to as narrow peak (NP) promoters.[6]

Intermediate promoters edit

"The intermediate transcription factor genes have early promoters, late transcription factor genes have intermediate promoters, and early transcription factor genes have late promoters, providing a cascade mechanism of regulation (4, 9, 10, 15, 22)."[7]

Minimal promoters edit

Diagram is of the βH-2K-DCR microlocus cassette and the β-globinpromoter. Credit: Michael Antoniou and Frank Grosveld.{{fairuse}}

There is "interaction between the dominant control region (DCR) and the promoter of the human β-globin gene. Expression analysis in [murine erythroleukemia] MEL cells has revealed that the DCR contains a number of elements capable of replacing the upstream (- 250 to - 100) erythroid-specific region of the promoter. The DCR strongly stimulates expression from a promoter possessing only a TATA box. However, this basic level of transcription is not induced upon erythroid differentiation of the cells. Mutational analysis of the minimal (- 100, noninducible) promoter shows that only the combination of the DCR and the CAC/CCAAT elements provides erythroid-specific transcription. These regions act synergistically to produce full regulated expression during erythroid differentiation."[8]

The "murine NF-E1 alone is incapable of inducing regulated expression on the minimal β-globin promoter (see [above diagram]) but needs to interact with at least one ubiquitous DNA-binding protein at a neighboring site ([above diagram], CP-1 at -160; deBoer et al. 1988)."[8]

"Only the minimal promoter is essential in the presence of the DCR."[8]

"The upstream part of the β-globin promoter confers inducible expression on the gene, mediated by the presence of at least one of the two NF-E1 and the (-150) CP-l-binding sites ([above diagram]; deBoer et al. 1988)".[8]

"Deletion analysis revealed that only the minimal part of the promoter is, in fact, sufficient for full regulated expression ([...], - 103). Thus, the upstream region of the promoter that contains the binding sites for the erythroid-specific transcription factor NF-E1 (see [above diagram]), like the enhancers, is also made completely redundant by the DCR."[8]

Hypotheses edit

  1. At least one promoter occurs within the proximal promoter of A1BG.

See also edit

References edit

  1. "gene". San Francisco, California: Wikimedia Foundation, Inc. December 13, 2012. Retrieved 2012-12-13.
  2. promoter. San Francisco, California: Wikimedia Foundation, Inc. 28 May 2014. Retrieved 2014-06-08. 
  3. "proximus". San Francisco, California: Wikimedia Foundation, Inc. 17 April 2014. Retrieved 2014-06-08.
  4. Thomas Shafee and Rohan Lowe (09 March 2017). "Eukaryotic and prokaryotic gene structure". WikiJournal of Medicine 4 (1): 2. doi:10.15347/wjm/2017.002. Retrieved 2017-04-06. 
  5. 5.0 5.1 T Juven-Gershon, JY Hsu, JWM Theisen, JT Kadonaga (June 2008). "The RNA polymerase II core promoter - the gateway to transcription". Current Opinion in Cell Biology 20 (3): 253-9. doi:10.1016/ PMID 18436437. 
  6. Rach EA, Winter DR, Benjamin AM, Corcoran DL, Ni T, Zhu J, Ohler U (January 2011). "Transcription initiation patterns indicate divergent strategies for gene regulation at the chromatin level". PLoS Genetics 7 (1): e1001274. doi:10.1371/journal.pgen.1001274. PMID 21249180. 
  7. Zhilong Yang, Sara E. Reynolds, Craig A. Martens, Daniel P. Bruno, Stephen F. Porcella and Bernard Moss (October 2011). "Expression profiling of the intermediate and late stages of poxvirus replication". Journal of Virology 85 (19): 9899-908. doi:10.1128/JVI.05446-11. Retrieved 2017-04-06. 
  8. 8.0 8.1 8.2 8.3 8.4 Michael Antoniou and Frank Grosveld (1990). "β-Globin dominant control region interacts differently with distal and proximal promoter elements". Genes & Development 4 (6): 1007-1013. doi:10.1101/gad.4.6.1007. Retrieved 2018-2-23. 

External links edit