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Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Probing The Genetic Code With Leucine Trna Variants, Peter Anderson Hall Oct 2022

Probing The Genetic Code With Leucine Trna Variants, Peter Anderson Hall

Electronic Thesis and Dissertation Repository

Mistranslation is an error in protein synthesis whereby the amino acids specified by the genetic code are misplaced by others in the growing polypeptide chain. The anticodon of tRNALeu can be altered allowing for the misincorporation of leucine at non-leucine codons. Observing the effect of tRNALeu variants on the viability of yeast and mammalian cells will provide information on their ability to cause mistranslation and potential relationship to genetic diseases. To explore this, a random pool of tRNALeu anticodonvariants was expressed in Saccharomyces cerevisiae. Furthermore, three mutant tRNALeu already sequenced from humans were expressed in …


Perseverance Of Protein Homeostasis Despite Mistranslation, Farah Hasan Aug 2022

Perseverance Of Protein Homeostasis Despite Mistranslation, Farah Hasan

Electronic Thesis and Dissertation Repository

Transfer RNAs (tRNAs) are essential for protein synthesis and translation fidelity. Some human tRNA variants may cause amino acid misincorporation: tRNAGly variants (tRNAGlyCCC, tRNAGlyGCC) have mutations that generate an alanine tRNA identity element (G3:U70), likely causing mis-aminoacylation of glycine tRNAs with alanine, while the tRNAAlaAGC G35C (tRNAAlaACC) variant may function similarly to mis-incorporate Ala at Gly codons by generating a Gly anticodon. I propose that these mistranslating tRNAs will disrupt protein homeostasis in mammalian cells. Although the tRNAGly and tRNAAla variants did not affect protein synthesis …


Mistranslating Trnas Alter The Heat Shock Activation By Hsf1, Rebecca Dib Aug 2022

Mistranslating Trnas Alter The Heat Shock Activation By Hsf1, Rebecca Dib

Undergraduate Student Research Internships Conference

Translation, or the production of protein from an mRNA blueprint, is among the most fundamental processes to life as we know it. tRNAs are essential to accurate translation, as they decode the codons of mRNA and recruit corresponding amino acids. Variant tRNAs with anticodon mutations can decrease translational fidelity by recruiting the incorrect amino acid, an aberrant process known as mistranslation. When proteins are produced with incorrect amino acid sequences, they may misfold. The heat shock response functions to alleviate cellular stress caused by misfolded proteins, either by refolding or targeting misfolded proteins for degradation. Hsf1 acts as a transcriptional …


Illuminating Transfer Rna Variants As Genetic Modifiers In Models Of Human Disease, Jeremy T. Lant Feb 2022

Illuminating Transfer Rna Variants As Genetic Modifiers In Models Of Human Disease, Jeremy T. Lant

Electronic Thesis and Dissertation Repository

Transfer RNAs (tRNAs) physically link the genetic code to an amino acid sequence, by recruiting amino acids to three-nucleotide codons in messenger RNAs. To ensure that the genetic code is translated as intended, tRNAs must be accurately aminoacylated and faithfully recognize codons in the ribosome during protein synthesis. Given the critical function of tRNAs, it has often been assumed that mutations in human tRNA genes would be either lethal to cells or not significantly impair tRNA function. My goal was to rigorously test this assumption in mammalian cell models, prompted by the recent discovery of unprecedented variation in human tRNA …


Implications And Applications Of Transfer Rna Variants That Mistranslate The Genetic Code, Matthew D. Berg Jan 2021

Implications And Applications Of Transfer Rna Variants That Mistranslate The Genetic Code, Matthew D. Berg

Electronic Thesis and Dissertation Repository

Genetic information is passed from DNA to RNA to protein through the processes of transcription and translation. Transfer RNAs (tRNA) are the adaptors that bring amino acids to the growing polypeptide chain during translation and decode the three base codons that define protein sequence. Mistranslation occurs when an amino acid different from what is specified by the genetic code is inserted into a protein. tRNA variants cause mistranslation by decreasing the accuracy of amino acid charging or by altering decoding at the ribosome. My goal was to characterize mistranslating tRNA variants, identify their effects on cells and determine mechanisms used …


Determining Whether The Nature Of The Amino Acid Substitution Or The Extent Of Mistranslation Affects The Impact Of Mistranslating Trnas In Saccharomyces Cerevisiae., Yanrui Zhu Apr 2020

Determining Whether The Nature Of The Amino Acid Substitution Or The Extent Of Mistranslation Affects The Impact Of Mistranslating Trnas In Saccharomyces Cerevisiae., Yanrui Zhu

Electronic Thesis and Dissertation Repository

Mistranslation occurs when an mRNA sequence is improperly decoded. Mistranslation can destabilize the proteome thus having a detrimental impact on the cell. tRNA variants with altered charging or decoding capabilities can increase mistranslation. Four mistranslating tRNAs were evaluated in yeast cells for their effect on growth, heat shock response, genetic interactions and cell morphology. Three of the tRNAs mistranslate at similar frequency, allowing for direct comparison of different amino acid substitutions. Each variant had distinct phenotypic consequences. Two of the tRNAs cause the same type of amino acid substitution but to different extents. The tRNA with the higher mistranslation frequency …