Biology subjects

Bartle, L.

Publications and source records attributed to Bartle, L..

3 recordsLinked to original sources

bioRxiv2024

A mechanism for telomere-specific telomere length regulation

Telomere length is a critical determinant of telomere function and hence chromosome stability. Critically short telomeres induce cellular senescence and division arrest, which eventually may lead to devastating age-related degenerative diseases. Conversely, maintenance of telomere length is a hallmark of cancer. How telomere set-length is established and molecular mechanisms for telomere-specific length regulation remained unknown. Here we detail a mechanism of a telomere-specific set-length regulation that causes drastic differences in telomere length between individual telomeres in the same cell. Indeed, the results show that telomerase recruitment is modulated in cis in a telomere-specific way. Increased Sir4 abundance on yeast TEL03L subtelomeric heterochromatin leads to a set-length maintenance that is two to three times higher than on any other telomere. Remarkably, the distal 15 kb of TEL03L are sufficient to transfer this telomere specific set-length regulation to another chromosome. Furthermore, a mutation in the telomere boundary element protein Tbf1 allows increased Sir4 binding on all telomeres and hence results in longer set-lengths. The results therefore will force a rethinking of telomere length regulation away from the generalized view that all telomeres are treated the same to a more telomere-specific treatment. HIGHLIGHTSO_LIRegulation of the set-length of telomeric repeats is telomere-specific. C_LIO_LITEL03L on yeast chromosome III displays a set-length regulation that confers an extremely long repeat tract. C_LIO_LITransferring the distal part of TEL03L onto chromosome XV is sufficient to impose the very long set-length regulation. C_LIO_LITelomere-specific tract set-length regulation depends on the alternate telomerase recruitment pathway involving Sir4 and yKU and the chromatin boundary protein Tbf1. C_LI GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=122 SRC="FIGDIR/small/598646v2_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@1c3bb52org.highwire.dtl.DTLVardef@13f338forg.highwire.dtl.DTLVardef@51f91aorg.highwire.dtl.DTLVardef@1b95ac0_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2021

Universal allometry from empirical parameters

Allometric settings of population dynamics models are appealing due to their parsimonious nature and broad utility when studying system level effects. Here, we parameterise the size-scaled Rosenzweig-Macarthur ODEs to eliminate prey-mass dependency. We define the functional response term to match experiments, and examine situations where metabolic theory derivations and observation diverge. We produce dynamics consistent with observation. Our parameterisation of the Rosenzweig-Macarthur system is an accurate minimal model across 15+ orders of mass magnitude.

ecology↗

bioRxiv2021

QTL mapping: an innovative method for investigating the genetic determinism of yeast-bacteria interactions in wine

The two most commonly used wine microorganisms, Saccharomyces cerevisiae yeast and Oenococcus oeni bacteria, are responsible for completion of alcoholic and malolactic fermentation (MLF), respectively. For successful co-inoculation, S. cerevisiae and O. oeni must be able to complete fermentation, however, this relies on compatibility between yeast and bacterial strains. For the first time, Quantitative Trait Loci (QTL) analysis was used to elucidate whether S. cerevisiae genetic makeup can play a role in the ability of O. oeni to complete MLF. Assessment of 67 progeny of an S. cerevisiae SBxGN cross, co-inoculated with a single O. oeni strain, SB3, revealed a major QTL linked to MLF completion by O. oeni. This QTL encompassed a well-known translocation, XV-t-XVI, that results in increased SSU1 expression and is functionally linked with numerous phenotypes including lag phase duration and sulfite export and production. A reciprocal hemizygosity assay was performed to elucidate the effect of the gene SSU1 in the SBxGN background. Our results instead revealed a strong effect of SSU1 haploinsufficiency on O. oenis ability to complete malolactic fermentation during co-inoculation, and paves the way for the implementation of QTL mapping projects for deciphering the genetic bases of microbial interactions. Key pointsFor the first time QTL analysis has been used to study yeast-bacteria interactions. A QTL encompassing a translocation, XV-t-XVI, was linked to MLF outcomes. S. cerevisiae SSU1 haploinsufficiency positively impacted MLF by O. oeni.

microbiology↗