Intrinsic termination

Intrinsic termination

Intrinsic termination (also called Rho-independent termination) is a mechanism in both eukaryotes and prokaryotes that causes mRNA transcription to be stopped. In this mechanism, the mRNA contains a sequence that can base pair with itself to form a stem-loop structure 7-20 base pairs in length that is also rich in Cytosine-Guanine base pairs. These bases form three hydrogen bonds between each other and are therefore particularly strong. Following the stem-loop structure is a chain of Uracil residues. The bonds between Uracil and Adenine are very weak. A protein bound to RNA polymerase (nusA) binds to the stem-loop structure tightly enough to cause the polymerase to temporarily stall. This pausing of the polymerase coincides with transcription of the poly-Uracil sequence. The weak Adenine-Uracil bonds destabilize the RNA-DNA duplex, causing it to unwind and dissociate from the RNA polymerase.

Stem-loop structures that are not followed by a poly-Uracil sequence cause the RNA polymerase to pause, but it will typically continue transcription after a brief time because the duplex is too stable to unwind far enough to cause termination.

Rho-independent transcription termination is a frequent mechanism underlying the activity of "cis"-acting RNA regulatory elements, such as riboswitches.

References

cite book
last= Lewin
first= Benjamin
title= Genes IX
year= 2007
publisher= Jones and Bartlett Publishers
location= Sudbury, MA
isbn= 0-7637-4063-2

ee also

Rho factor


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • Transcription (genetics) — Transcription is the process of creating a complementary RNA copy of a sequence of DNA.[1] Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language that can be converted back and forth from DNA to RNA by …   Wikipedia

  • Coactivator (genetics) — A coactivator is a protein that increases gene expression by binding to an activator (or transcription factor) which contains a DNA binding domain. The coactivator is unable to bind DNA by itself.[1][2][3] The coactivator can enhance… …   Wikipedia

  • Prokaryotic transcription — is the process in which messenger RNA transcripts of genetic material in prokaryotes are produced, to be translated for the production of proteins. Prokaryotic transcription occurs in the cytoplasm alongside translation. Unlike in eukaryotes,… …   Wikipedia

  • Terminator (genetics) — In genetics, a terminator, or transcription terminator is a section of genetic sequence that marks the end of gene or operon on genomic DNA for transcription. In prokaryotes, two classes of transcription terminators are known: Intrinsic… …   Wikipedia

  • DNA methylation — Illustration of a DNA molecule that is methylated at the two center cytosines. DNA methylation plays an important role for epigenetic gene regulation in development and disease. DNA methylation is a biochemical process that is important for… …   Wikipedia

  • Operon — A typical operon In genetics, an operon is a functioning unit of genomic DNA containing a cluster of genes under the control of a single regulatory signal or promoter.[1][2] The genes are tr …   Wikipedia

  • Enhancer (genetics) — In genetics, an enhancer is a short region of DNA that can be bound with proteins (namely, the trans acting factors, much like a set of transcription factors) to enhance transcription levels of genes (hence the name) in a gene cluster. While… …   Wikipedia

  • DNA methyltransferase — N 6 DNA Methylase crystal structure of type i restriction enzyme ecoki m protein (ec 2.1.1.72) (m.ecoki) Identifiers Symbol N6 Mtase Pfam …   Wikipedia

  • Stem-loop — intramolecular base pairing is a pattern that can occur in single stranded DNA or, more commonly, in RNA. The structure is also known as a hairpin or hairpin loop. It occurs when two regions of the same molecule, usually palindromic (reads the… …   Wikipedia

  • Insulator (genetics) — For electrical insulator, see Insulator (Electrical). For other uses, see Insulation (disambiguation). An insulator is a genetic boundary element that plays two distinct roles in gene expression, either as an enhancer blocking element, or more… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”