Primer (molecular biology)

As primer ( Pl: primer; IPA: [ pʁaɪ̯mɐ ] ) in the molecular biology denotes an oligonucleotide which serves as the starting point for DNA replicating enzymes such as DNA polymerase.

DNA polymerases require a hydroxyl group as a starting point for their first coupling reaction. Primer set with its 3'- OH end of a suitable hydroxy available. Primers may consist of both DNA and RNA from. During replication in prokaryotes and eukaryotes, RNA serves as primer material. In prokaryotes primase synthesized, also known as protein dnaG, the primer sequences. In eukaryotes, the DNA polymerase has an α Primasefunktion. A special case is the DNA synthesis at the telomeres of eukaryotic cells dar. Here is the polymerizing enzyme telomerase, the 3'- OH end of the DNA as a primer sequence. In prokaryotes, the emerging replication primers are removed by the 5'- 3 'exonuclease activity of the polymerase I RNase H, or by. In eukaryotic cells, the primers are δ by displacing DNA synthesis of the polymerase and restriction is removed by the flap endonuclease.

Also, in the in vitro amplification of DNA, for example in the polymerase chain reaction (PCR), DNA sequencing, or in the reverse transcription primers are required. This can be calculated using the primers specific to the DNA segment to be amplified set.

Primer design

The specific design of primers is referred to as primer design. For PCR are nucleotide sequences that flank the DNA segment to be amplified, is determined. According to these sequences suitable primer sequences are now produced by phosphoramidite synthesis. A primer in this case each represented the opposite strand to his "primer partner." Primers for PCR reactions typically have a length of 18-30 nucleotides. Various biotechnology companies now offer customized primers for molecular biology applications. Tailored mismatch primers can be introduced via the PCR technique also targeted mutations in genes such as consist in the replacement of an amino acid.