The p27 cis-regulatory element is a structured G/C rich RNA element which is involved in controlling

cell cycle The cell cycle, or cell-division cycle, is the series of events that take place in a cell that cause it to divide into two daughter cells. These events include the duplication of its DNA ( DNA replication) and some of its organelles, and sub ...

regulated

translation Translation is the communication of the Meaning (linguistic), meaning of a #Source and target languages, source-language text by means of an Dynamic and formal equivalence, equivalent #Source and target languages, target-language text. The ...

of the p27^kip protein in human cells. The p27^kip1 protein is involved in cell cycle regulation and belongs to the Cip/Kip family of

cyclin dependent kinase Cyclin-dependent kinases (CDKs) are the families of protein kinases first discovered for their role in regulating the cell cycle. They are also involved in regulating transcription, mRNA processing, and the differentiation of nerve cells. They ...

(CDK)inhibitors. These inhibitors possess an N-terminal CDK-inhibitory domain which binds to the

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binding pocket of the kinase and modulates its function. This p27 cis-regulatory element is 114

nucleotides Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules wi ...

in length and is located at the very 5' end of the

5'UTR The 5′ untranslated region (also known as 5′ UTR, leader sequence, transcript leader, or leader RNA) is the region of a messenger RNA (mRNA) that is directly upstream from the initiation codon. This region is important for the regulation of ...

of the p27

mRNA In molecular biology, messenger ribonucleic acid (mRNA) is a single-stranded molecule of RNA that corresponds to the genetic sequence of a gene, and is read by a ribosome in the process of synthesizing a protein. mRNA is created during the ...

. It contains a small open reading frame (ORF) of 29 amino acids which is preceded by and overlaps with a G/C-rich

hairpin A hairpin or hair pin is a long device used to hold a person's hair in place. It may be used simply to secure long hair out of the way for convenience or as part of an elaborate hairstyle or coiffure. The earliest evidence for dressing the hai ...

domain. This hairpin domain is predicted to form multiple stable stem loops with similar free energy. Both the open reading frame and the stem loop elements contribute to cell cycle-regulated translation of the p27 mRNA. The structure of the G/C rich element appears to be important to its regulatory function as replacement of the G/C rich region with an unstructured sequence has a greater effect on regulation of translation than a simple deletion of part of the G/C rich region. It has been suggested that cell cycle specific binding proteins may favour one of the predicted structures in the G/C region thereby promoting conformational states which could regulate downstream translation. This element was initially characterised in human cells but has predicted homologs in mice and chickens.

References

External links

* {{DEFAULTSORT:P27 Cis-Regulatory Element Cis-regulatory RNA elements