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A prion / ˈ p r iː ɒ n / ⓘ is a misfolded protein that induces misfolding in normal variants of the same protein, leading to cellular death. Prions are responsible for prion diseases, known as transmissible spongiform encephalopathy (TSEs), which are fatal and transmissible neurodegenerative diseases affecting both humans and animals.
In some types of prion in fungi this change is continuous and direct; the information flow is Protein → Protein. Some scientists such as Alain E. Bussard and Eugene Koonin have argued that prion-mediated inheritance violates the central dogma of molecular biology.
The abnormal protein PrP Sc accumulates in the brain and destroys nerve cells, which leads to the mental and behavioral features of prion diseases. [citation needed] Several other changes in the PRNP gene (called polymorphisms) do not cause prion diseases but may affect a person's risk of developing these diseases or alter the course of the ...
Another example is seen in prions, special proteins that are capable of changing the structure of normal proteins to match their own. The prions use themselves as a template and then edit the folding of normal proteins to match their own folding pattern. The changes in the protein folding results in an alteration in the normal protein's function.
It is, however, classified with the transmissible spongiform encephalopathies (TSE) due to the causative role played by PRNP, the human prion protein. [2] GSS was first reported by the Austrian physicians Josef Gerstmann, Ernst Sträussler and Ilya Scheinker in 1936. [3] [4] Familial cases are associated with autosomal-dominant inheritance. [5]
Structural inheritance or cortical inheritance is the transmission of an epigenetic trait in a living organism by a self-perpetuating spatial structures. This is in contrast to the transmission of digital information such as is found in DNA sequences, which accounts for the vast majority of known genetic variation.
This makes prions a metastable, dominant mechanism for inheritance that relies solely on the conformation of the protein. Many proteins containing prion domains play a role in gene expression or RNA binding, which is how an alternative conformation can give rise to phenotypic variation.
Circularization of the mRNA transcript is mediated by proteins interacting with the 5' cap and poly(A) tail. The poly(A) tail contains binding sites for poly(A) binding proteins (PABPs). These proteins cooperate with other factors to affect the export, stability, decay, and translation of an mRNA.