Leader sequence
As a leader sequence or leader sequence in which is molecular biology , the nucleotide sequence of the untranslated region from the 5 'end of a mRNA , respectively. This 5'-UTR sequence extends to the starting point of translation ( start codon ) and can be of various lengths (a few to several hundred nucleotides ). In addition to the binding site (RBS) required for binding the mRNA to a ribosome - the Shine-Dalgarno sequence in the case of prokaryotic mRNA , and a Kozak sequence in the case of eukaryotic mRNA - it often contains further regulatory effective sequence sections which can be used to influence the translation efficiency .
The leader sequence is a control sequence on the mRNA and is not translated into the protein encoded by the subsequent open reading frame . It can contain various regulatory sequences that represent binding sites for specific RNA-binding proteins and factors or can form special structural features such as hairpin structures through internal folds of the mRNA . These can, for example, also be those that enable attenuation . In this case the mRNA can fold into alternative secondary structures. One causes the transcription to be terminated prematurely (termination signal), while another allows the transcription to be continued and thus the subsequent translation.
At the level of the DNA template for the RNA transcript, the sequence is found between the transcription start point and the translation start point for the protein encoded by a gene.
Individual evidence
- ↑ Entry leader sequence in the lexicon of biology on Spektrum.de; accessed on February 11, 2020.
literature
- Rolf Knippers: Molecular Genetics. 8th revised edition. Georg Thieme Verlag, Stuttgart et al. 2001, ISBN 3-13-477008-3 .