Cis element

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As a cis element or cis-acting element (from the Latin cis , this side '), a certain section in the genetic information is referred to in biology that plays a role in the regulation of a gene that is on the same DNA molecule as this ( molecularly considered on this side). This regulatory sequence segment does not have to encode either RNA or protein and can be in the reading direction before or after the coding sequence of the associated gene, or within (also in an intron ).

Cis elements upstream of a gene often represent binding motifs for (special) transcription factors , which act here as trans-acting factors (from the Latin trans `` beyond ''), from a molecular point of view, intervening in the regulation of the transcription of this gene. If cis-elements lead to an inhibition of the transcription, they are called silencers . Cis elements that lead to an increase in transcription and are not part of promoters are called enhancers . An example of this is the DNAse-hypersensitive site of the lysozyme gene , which (6.1 kb) lies before the start of transcription and increases gene expression through interaction with transcription factors . The totality of the cis / trans activities in a gene locus determines the intensity with which the RNA polymerase carries out the transcription.

One speaks of cis elements in biological processes such as recombination. For example, in the tumor-inducing Ti plasmid of agrobacteria, cis elements can be found in the form of repetitive sequences (repetition motif of 25 bases ), which in the circular plasmid are left and right borders (left border [lb] and right border [rb]). flank the t-DNA. These are seen as essential cis-elements for the transfer of the t-DNA during the transfer into the plant cell.

Individual evidence

  1. ^ T. Grewal, M. Theisen, U. Borgmeyer, T. Grussenmeyer, RA Rupp, A. Stief, F. Qian, A. Hecht, AE Sippel: The -6.1-kilobase chicken lysozyme enhancer is a multifactorial complex containing several cells -type-specific elements. In: Molecular and cellular biology. Volume 12, Number 5, May 1992, pp. 2339-2350. PMID 1569954 , PMC 364406 (free full text).
  2. ↑ NS Yadav, J. Vanderleyden et al.: Short direct repeats flank the t-DNA on a nopaline ti-plasmid. In: Proceedings of the National Academy of Sciences -Biological Sciences. Volume 79, No. 20, 1982, pp. 6322-6326. PMID 16593241 , PMC 347113 (free full text).
  3. ↑ T. Komori, T. Imayama et al .: Current status of binary vectors and superbinary vectors. In: Plant Physiology. Volume 145, No. 4, 2007, pp. 1155-1160. Current status of binary vectors and superbinary vectors. PMID 18056865 , PMC 2151727 (free full text).

literature

  • Peter Schopfer, Axel Brennecke: Plant Physiology. 6th edition. Elsevier Spektrum Akademischer Verlag, Munich et al. 2005, ISBN 3-8274-1561-6 .