Polyribosome

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polyribosome

[‚päl·i′rī·bə‚sōm]
(cell and molecular biology)

Polyribosome

 

(or polysome), a protein-synthesizing complex in living cells; each complex is composed of one molecule of messenger ribonucleic acid (mRNA) and a few or several ribosomes connected to the mRNA molecule.

Polyribosomes are formed by the successive addition of ribosomes to mRNA. As they pass along the mRNA one by one, the ribosomes “read out” the information contained in the mRNA; it means that each ribosome synthesizes one molecule of protein (polypeptide chain) according to the program recorded in the mRNA. Protein synthesis in the cell is effected primarily by polyribosomes rather than by individual ribosomes.

References in periodicals archive ?
Laforin, defective in the progressive myoclonus epilepsy of Lafora type, is a dual-specificity phosphatase associated with polyribosomes. Hum.
A greater density of submucosal neurons was verified by Giemsa technique that can be considered a pan-neuronal technique because it stains neurons due to the affinity of the stain with structures formed by acid proteins, especially polyribosomes. Based on the staining of enteric neurons by Giemsa technique (Barbosa), they classify neurons according to the cytoplasm basophilia and state that this technique allows to visualize polyribosome disintegration (Nissl' corpuscles) in the neuronal chromatolysis processes (Sant'Ana et al., 1997).
Kissing complex RNAs mediate interaction between the fragile-X mental retardation protein KH2 domain and brain polyribosomes. Genes Dev 2005;19:903-918.
Homogenized preparations of the specific developmental stages under study were ultracentrifuged for analysis of the distribution of ribosomes in monoribosomes and polyribosomes. Individuals were enumerated and 100,000 were prepared for each analysis.
Export proteins are synthesized on polyribosomes bound to the rough endoplasmic reticulum of the hepatocyte; in contrast, protein destined for intracellular use are synthesized on free rather than bound polyribosome (Podolsky and Isselbacher, 1991).
Additional features of the tumor cells included moderately abundant mitochondria, stacks of rough endoplasmic reticulum, and polyribosomes.
There was increase in free ribosomes (polyribosomes) number at 15 min, which tended to decrease throughout the post-absorption period.
The cytoplasm contained many mitochondria, prominent Golgi apparatus, numerous polyribosomes, moderate endoplasmic reticulum, a few lipid droplets, and, focally, intermediate filaments.
Mercury compounds can bind to the RNA of tobacco mosaic viruses (Katz & Santilli, 1962), several synthetic polyribosomes, and yeast soluble RNA (Kawade, 1963).
Perinuclear cistern is normally dilated abundant free ribosomes, rugose endoplasmic reticulum, polyribosomes and a few mitochondria can be observed in the small cytoplasm while microtubules are not.
The exact percentage of glassy cells needed to make the diagnosis of GCC is not well established, but it may range from 30% to 100%[1,9] Ultrastructurally, glassy cells may show intermediate filaments, polyribosomes, tonofibrils, and desmosomes.