Recombinant Saccharomyces cerevisiae Uncharacterized protein YOR097C (YOR097C)

What is currently known about YOR097C and its genomic context?

YOR097C is a hypothetical protein-coding gene in Saccharomyces cerevisiae S288C with Entrez Gene ID 854264 . It is located on chromosome XV in a genomic region that has shown particular characteristics in multiple studies. Most notably, YOR097C marks one boundary of a chromosomal segment (YOR097C-YOR192C) that has demonstrated significantly elevated microsatellite instability compared to flanking regions . The protein is not essential for viability, as demonstrated by viable deletion strains in the yeast knockout collection .

Current annotation data:

Are there known issues with YOR097C deletion strains in common laboratory collections?

Yes, researchers should exercise caution when working with YOR097C deletion strains from the Saccharomyces Genome Deletion Project. The 96 strains with disruptions of the ORFs between YOR097C and YOR192C were produced by a single lab and have been found to contain an additional mutation in the MSH3 mismatch repair gene . This mutation results in significantly elevated microsatellite instability, with rates increasing from 1 × 10^-5 to 5 × 10^-4 compared to regions outside this chromosomal segment .

This finding illustrates an important caveat when using publicly available deletion collections - the progenitor "wild-type" strain used to generate this set acquired a secondary mutation that affects genome stability. For accurate studies, it's essential to confirm the genotype of these strains or recreate them independently .

What genetic interactions have been identified for YOR097C?

High-throughput genetic interaction screening has identified a negative genetic interaction between YOR097C and BYE1 with a quantitative SGA score of -0.1525 (p-value = 6.765E-5) . Negative genetic interactions occur when mutations/deletions in separate genes, each causing minimal phenotypes alone, result in more severe fitness defects when combined in the same cell under specific conditions .

Genetic interaction data for YOR097C:

This interaction was detected in a global genetic interaction network study that constructed more than 23 million double mutants and identified approximately 550,000 negative and 350,000 positive genetic interactions .

How does the chromosomal location of YOR097C affect its study?

The location of YOR097C at the boundary of a region with high microsatellite instability makes it intriguing for genome stability research. Studies have shown that all 12 insertions in the region between YOR097C and YOR192C displayed significantly elevated rates of microsatellite instability compared to insertions outside this region .

Notably, the transition between high and low instability is abrupt, occurring precisely between ORFs YOR096W and YOR097C at one junction . This positioning suggests that YOR097C might be involved in or affected by localized genomic features that influence mutation rates or DNA repair efficiency.

What methods should I use to characterize an uncharacterized protein like YOR097C?

To characterize YOR097C, a multi-tiered experimental approach is recommended:

• Confirmation of deletion phenotypes: First verify your YOR097C deletion strain by PCR and sequencing to ensure it doesn't contain the MSH3 mutation found in the deletion collection .

• Genome stability assays: Given YOR097C's location in a region associated with microsatellite instability, employ recombination assays such as the leu2 direct-repeat recombination reporter to assess if YOR097C deletion affects genome stability.

• High-throughput replica-pinning methodology: This approach enables detection of low-frequency events like spontaneous mutations or recombination . This technique involves:

  • Use of 1536 format pads to pin strains in 384 format

  • Amplification by parallel high-throughput replica-pinning (analyzing ~18 colonies per strain)

  • Extended incubation time to allow accumulation of spontaneous mutations

  • Calculation of event frequency as a proxy for mutation/recombination rate

• Fluctuation tests: Measure forward mutation rates at reporter loci like CAN1 or URA3 . This established method can determine if YOR097C affects mutation rates across the genome.

How can CRISPR/Cas9 be utilized to study YOR097C function?

CRISPR/Cas9 offers powerful approaches for YOR097C characterization:

• Markerless genome editing: Create precise modifications without selection markers, which is particularly valuable for studying uncharacterized genes where marker effects might confound phenotype analysis .

• Structural modifications: Generate specific mutations, domain deletions, or tag insertions to study protein function and localization. This approach benefits from yeast's efficient homologous recombination .

• Multiplexed editing: Simultaneously modify YOR097C and potential interacting genes identified through genetic screens to investigate genetic relationships .

The protocol involves:

• Designing sgRNAs with high expression and stability in yeast

• Delivering sgRNAs through methods that select for cells proficient in gap repair

• Using homology-directed repair to introduce precise modifications

These techniques allow high-efficiency, markerless editing that can be multiplexed without needing a selection marker, facilitating more complex experimental designs .

Could YOR097C be involved in DNA repair or recombination pathways?

While direct evidence linking YOR097C to DNA repair is limited, several lines of investigation suggest this possibility:

• Its chromosomal location at the boundary of a region with elevated microsatellite instability is noteworthy . Microsatellite instability is typically associated with defects in DNA mismatch repair.

• Researchers have identified 35 genes whose deletion results in elevated spontaneous direct-repeat recombination, many with homologs in humans . Systematic genome-wide screens have been effective in identifying such genes.

• Genome-wide studies for genes suppressing genome instability have revealed both known and previously unidentified factors . The approach used pathway reconstruction based on genetic interactions, which could be applied to investigate YOR097C's potential role.

To test YOR097C's involvement in DNA repair:

• Measure recombination rates using direct-repeat reporters

• Assess sensitivity to DNA damaging agents

• Analyze genetic interactions with known DNA repair genes

• Examine mutation spectrum in YOR097C deletion strains

How does mutation rate vary across the chromosome where YOR097C is located, and could this affect its function?

Research has shown that mutation rates vary significantly across the yeast genome, with up to 6-fold variation across a single chromosome that correlates with replication timing .

For YOR097C, located on chromosome XV, the regional context is particularly significant. The abrupt transition between high and low microsatellite instability occurs precisely at the boundary where YOR097C is located . This suggests that YOR097C might be influenced by or participate in regional effects on genome stability.

Key observations about the chromosomal region including YOR097C:

• All 12 insertions between YOR097C and YOR192C showed significantly elevated rates of microsatellite instability

• The transition between high and low instability is abrupt at YOR097C

• Different genomic locations vary in their susceptibility to mutations and recombination

This positioning raises interesting research questions about whether YOR097C's function might relate to maintaining genome stability in this transition zone.

What bioinformatic approaches can help predict YOR097C function?

Bioinformatic analysis can provide valuable insights into YOR097C function despite limited experimental data:

• Genetic interaction network analysis: The negative genetic interaction with BYE1 can be contextualized within larger interaction networks to predict functional relationships.

• Three-hypothesis approach: Following the methodology described in search result :

  • Known and unidentified genes that suppress genome instability share phenotypic properties

  • Systematic and random errors will not obscure useful information in genome-wide datasets

  • Genetic interactions determined by synergistic growth defects provide information about other biological processes

• Integrated data analysis: Combine genetic interaction data with:

  • Phenotypic information from genome-wide screens

  • Evolutionary conservation patterns

  • Expression correlation data

  • Protein domain analysis

This integrated approach has successfully identified previously uncharacterized genes involved in genome stability pathways .

What experimental systems can detect if YOR097C affects genome stability?

Several experimental systems can assess YOR097C's potential role in genome stability:

• Direct-repeat recombination assay: Utilize the leu2ΔEcoRI-URA3-leu2ΔBstEII reporter . After integration into yeast strains, recombination events are detected as papillae on medium lacking leucine. The system allows measurement of recombination rates through fluctuation tests:

  Protocol overview:

  • Streak single colonies on YPD

  • Incubate at 30°C for 24h

  • Replica-plate to medium lacking leucine

  • Score recombination events as papillae

  • Calculate recombination rates using fluctuation analysis

• Mother Enrichment Program (MEP): This system can detect low-frequency mutation events during replicative aging . The approach involves:

  • Activating the MEP to induce replicative aging

  • Using escaper formation as a reporter for spontaneous mutation events

  • High-throughput replica-pinning to analyze multiple colonies per strain

  • Calculating escaper frequency as a proxy for mutation rate

• Microsatellite instability assay: Given the region's known microsatellite instability, a URA3-GT reporter can measure instability rates . This system has detected rates varying from 1 × 10^-5 to 5 × 10^-4 depending on genomic location .

These complementary approaches provide a comprehensive assessment of YOR097C's potential role in maintaining genome stability.