Related Experiment Video
Updated: Jun 12, 2026
10:41
Identifying Amino Acid Overproducers Using Rare-Codon-Rich Markers
Published on: June 24, 2019
Oligopeptide-repeat expansions modulate 'protein-only' inheritance in yeast.
1Howard Hughes Medical Institute, Department of Molecular Genetics and Cell Biology, University of Chicago, Illinois 60637, USA.
Nature
|August 17, 1999
Summary
Repeat expansions in yeast Sup35 protein induce [PSI+] elements, a novel genetic inheritance. This suggests a link between yeast prions and mammalian prion diseases, offering insights into protein-based inheritance mechanisms.
Area of Science:
- Molecular Biology
- Genetics
- Neuroscience
Background:
- The yeast [PSI+] element is a non-Mendelian genetic inheritance system.
- Mammalian prion diseases are linked to the prion protein (PrP).
- The molecular mechanisms of protein-based inheritance are poorly understood.
Purpose of the Study:
- To investigate the role of repeat expansions in the yeast Sup35 protein.
- To explore the potential link between yeast [PSI+] elements and mammalian prion diseases.
- To understand the conformational changes in protein-based inheritance.
Main Methods:
- Replacing the wild-type SUP35 gene with a repeat-expansion mutation.
- In vitro analysis of peptide conformations and higher-order structure formation.
- Comparing the behavior of wild-type and repeat-expansion peptides.
Main Results:
- Repeat-expansion mutations in SUP35 induced new [PSI+] elements in yeast.
- Denatured repeat-expansion peptides rapidly formed beta-sheet-rich structures in vitro.
- Wild-type peptides formed higher-order structures more slowly.
Conclusions:
- Repeat expansions are a key factor in initiating [PSI+] elements.
- Protein conformational changes are central to protein-based inheritance.
- Findings suggest a mechanistic link between yeast prion phenomena and mammalian neurodegenerative prion diseases.
Related Concept Videos
02:32Exon Recombination
The evolution of new genes is critical for speciation. Exon recombination, also known as exon shuffling or domain shuffling, is an important means of new gene formation. It is observed across vertebrates, invertebrates, and in some plants such as potatoes and sunflowers. During exon recombination, exons from the same or different genes recombine and produce new exon-intron combinations, which might evolve into new genes.
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Exon shuffling follows “splice frame rules.” Each exon has three reading...
01:29Coordination of Gene Expression Processes in Bacteria
The DNA replication, transcription, and translation processes are intricately coupled in bacteria, allowing efficient gene expression and rapid protein synthesis. While this physical and functional coordination is advantageous, it introduces challenges that bacteria overcome through specific regulatory mechanisms.Coupling of Replication, Transcription, and TranslationThe coupling of replication, transcription, and translation is a hallmark of bacterial gene expression. As the replisome unwinds...
01:21Repressible Operon: trp Operon
The trp operon in Escherichia coli exemplifies a repressible operon. It regulates the synthesis of tryptophan through repressor-mediated transcriptional control and attenuation. This dual regulatory mechanism ensures tryptophan biosynthesis occurs only when needed, conserving cellular resources.Structure of the trp OperonThe trp operon consists of five structural genes (trpE, trpD, trpC, trpB, and trpA) that encode enzymes for tryptophan biosynthesis. These genes are transcribed as a single...
01:17Gene Regulation During Sporulation
Sporulation is a complex developmental process that allows certain Gram-positive bacteria, such as Bacillus subtilis and Clostridium species, to survive extreme environmental conditions. This process is tightly regulated by a series of signaling cascades and transcriptional controls, ensuring the formation of a highly resistant endospore.Sporulation is triggered by unfavorable conditions, such as nutrient depletion, and is governed by a phosphorelay system. One of the sensor kinases, such as...
01:23Stringent Response in E. coli
Bacterial growth is closely tied to nutrient availability, with cells proliferating exponentially under favorable conditions and entering a stationary phase when resources become scarce. This transition is mediated by a regulatory mechanism known as the stringent response, which allows bacteria to adapt to nutrient deprivation by modulating gene expression and metabolic activity.During nutrient scarcity, intracellular amino acid levels decline. It results in the accumulation of uncharged tRNAs...
01:22Bioreactor Controls-III
Strain improvement is a foundational strategy in industrial microbiology aimed at maximizing microbial productivity, particularly because natural isolates typically yield commercially valuable products in very low concentrations. Although optimizing the culture medium and environmental conditions can improve yields, these adjustments are inherently limited by the organism’s genetic potential. As a result, the focus shifts toward genetic modifications to enhance biosynthetic capacity. The...