Proximity labeling reveals new functional relationships between meiotic recombination proteins in S. cerevisiae.

Several protein ensembles facilitate crossover recombination and the associated assembly of synaptonemal complex (SC) during meiosis. In yeast, meiosis-specific factors including the DNA helicase Mer3, the "ZZS" complex consisting of Zip4, Zip2, and Spo16, the RING-domain protein Zip3, and the MutSγ heterodimer collaborate with crossover-promoting activity of the SC component, Zip1, to generate crossover-designated recombination intermediates. These ensembles also promote SC formation - the organized assembly of Zip1 with other structural proteins between aligned chromosome axes.

A flexible consistent framework for modelling multiple interacting environmental responses to management in space and time.

Management of resources is often a large-scale task addressed using many small-scale interventions. The range of scales at which organisms respond to those interventions, along with the many outcomes which management aims to achieve can make determining the success of management complex. Environmental flow is an example of management where there is a recognized need for managers to demonstrate the impact of their actions by integrating different types of environmental responses.

Can freshwater plants and algae act as an effective feed supplement to reduce methane emissions from ruminant livestock?

Methane production by livestock is a substantial component of greenhouse gas emissions worldwide. The marine red algae, Asparagopsis taxiformis, has been identified as a possible supplement in livestock feeds due to its potent inhibition of methane production but currently is unable to be produced at scale. Finding additional taxa that inhibit methane production is therefore desirable.

Meiosis in budding yeast.

Meiosis is a specialized cell division program that is essential for sexual reproduction. The two meiotic divisions reduce chromosome number by half, typically generating haploid genomes that are packaged into gametes. To achieve this ploidy reduction, meiosis relies on highly unusual chromosomal processes including the pairing of homologous chromosomes, assembly of the synaptonemal complex, programmed formation of DNA breaks followed by their processing into crossovers, and the segregation of homologous chromosomes during the first meiotic division.

The genetic basis for panicle trait variation in switchgrass (Panicum virgatum).

We investigate the genetic basis of panicle architecture in switchgrass in two mapping populations across a latitudinal gradient, and find many stable, repeatable genetic effects and limited genetic interactions with the environment. Grass species exhibit large diversity in panicle architecture influenced by genes, the environment, and their interaction. The genetic study of panicle architecture in perennial grasses is limited.

Histone variant H2A.Z promotes meiotic chromosome axis organization in Saccharomyces cerevisiae.

Progression through meiosis is associated with significant reorganization of chromosome structure, regulated in part by changes in histones and chromatin. Prior studies observed defects in meiotic progression in yeast strains lacking the linker histone H1 or variant histone H2A.Z.

A role for synaptonemal complex in meiotic mismatch repair.

A large subset of meiotic recombination intermediates form within the physical context of synaptonemal complex (SC), but the functional relationship between SC structure and homologous recombination remains obscure. Our prior analysis of strains deficient for SC central element proteins demonstrated that tripartite SC is dispensable for interhomolog recombination in Saccharomyces cerevisiae. Here, we report that while dispensable for recombination per se, SC proteins promote efficient mismatch repair at interhomolog recombination sites.

QTL × environment interactions underlie ionome divergence in switchgrass.

Ionomics measures elemental concentrations in biological organisms and provides a snapshot of physiology under different conditions. In this study, we evaluate genetic variation of the ionome in outbred, perennial switchgrass in three environments across the species' native range, and explore patterns of genotype-by-environment interactions. We grew 725 clonally replicated genotypes of a large full sib family from a four-way linkage mapping population, created from deeply diverged upland and lowland switchgrass ecotypes, at three common gardens.

PI 3-kinase delta enhances axonal PIP to support axon regeneration in the adult CNS.

Peripheral nervous system (PNS) neurons support axon regeneration into adulthood, whereas central nervous system (CNS) neurons lose regenerative ability after development. To better understand this decline whilst aiming to improve regeneration, we focused on phosphoinositide 3-kinase (PI3K) and its product phosphatidylinositol (3,4,5)-trisphosphate (PIP ). We demonstrate that adult PNS neurons utilise two catalytic subunits of PI3K for axon regeneration: p110α and p110δ.

Genetic Associations in Four Decades of Multienvironment Trials Reveal Agronomic Trait Evolution in Common Bean.

Multienvironment trials (METs) are widely used to assess the performance of promising crop germplasm. Though seldom designed to elucidate genetic mechanisms, MET data sets are often much larger than could be duplicated for genetic research and, given proper interpretation, may offer valuable insights into the genetics of adaptation across time and space. The Cooperative Dry Bean Nursery (CDBN) is a MET for common bean () grown for > 70 years in the United States and Canada, consisting of 20-50 entries each year at 10-20 locations.

SYCP2 Translocation-Mediated Dysregulation and Frameshift Variants Cause Human Male Infertility.

Unexplained infertility affects 2%-3% of reproductive-aged couples. One approach to identifying genes involved in infertility is to study subjects with this clinical phenotype and a de novo balanced chromosomal aberration (BCA). While BCAs may reduce fertility by production of unbalanced gametes, a chromosomal rearrangement may also disrupt or dysregulate genes important in fertility.

Population Genetics of the Highly Polymorphic Gene Family.

Plant nucleotide-binding domain and leucine-rich repeat containing (NLR) genes provide some of the most extreme examples of polymorphism in eukaryotic genomes, rivalling even the vertebrate major histocompatibility complex. Surprisingly, this is also true in , a predominantly selfing species with low heterozygosity. Here, we investigate how gene duplication and intergenic exchange contribute to this extraordinary variation.

Crossover recombination and synapsis are linked by adjacent regions within the N terminus of the Zip1 synaptonemal complex protein.

Accurate chromosome segregation during meiosis relies on the prior establishment of at least one crossover recombination event between homologous chromosomes. Most meiotic recombination intermediates that give rise to interhomolog crossovers are embedded within a hallmark chromosomal structure called the synaptonemal complex (SC), but the mechanisms that coordinate the processes of SC assembly (synapsis) and crossover recombination remain poorly understood. Among known structural components of the budding yeast SC, the Zip1 protein is unique for its independent role in promoting crossover recombination; Zip1 is specifically required for the large subset of crossovers that also rely on the meiosis-specific MutSγ complex.

Text Message Quality Improvement Project for Influenza Vaccine in a Low-Resource Largely Latino Pediatric Population.

Children with asthma are targeted for influenza vaccine because of their vulnerability to complications, particularly those with low income or family preference for Spanish language. We used text messaging to encourage caregivers to vaccinate. Participants were children (aged >6 months), predominantly low income and Latino, with an asthma diagnosis attending a pediatric clinic.

A conserved filamentous assembly underlies the structure of the meiotic chromosome axis.

The meiotic chromosome axis plays key roles in meiotic chromosome organization and recombination, yet the underlying protein components of this structure are highly diverged. Here, we show that 'axis core proteins' from budding yeast (Red1), mammals (SYCP2/SYCP3), and plants (ASY3/ASY4) are evolutionarily related and play equivalent roles in chromosome axis assembly. We first identify 'closure motifs' in each complex that recruit meiotic HORMADs, the master regulators of meiotic recombination.

The genomic landscape of molecular responses to natural drought stress in Panicum hallii.

Environmental stress is a major driver of ecological community dynamics and agricultural productivity. This is especially true for soil water availability, because drought is the greatest abiotic inhibitor of worldwide crop yields. Here, we test the genetic basis of drought responses in the genetic model for C perennial grasses, Panicum hallii, through population genomics, field-scale gene-expression (eQTL) analysis, and comparison of two complete genomes.

HO Endonuclease-Initiated Recombination in Yeast Meiosis Fails To Promote Homologous Centromere Pairing and Is Not Constrained To Utilize the Dmc1 Recombinase.

Crossover recombination during meiosis is accompanied by a dramatic chromosome reorganization. In , the onset of meiotic recombination by the Spo11 transesterase leads to stable pairwise associations between previously unassociated homologous centromeres followed by the intimate alignment of homologous axes via synaptonemal complex (SC) assembly. However, the molecular relationship between recombination and global meiotic chromosome reorganization remains poorly understood.

Reduced dosage of the chromosome axis factor Red1 selectively disrupts the meiotic recombination checkpoint in Saccharomyces cerevisiae.

Meiotic chromosomes assemble characteristic "axial element" structures that are essential for fertility and provide the chromosomal context for meiotic recombination, synapsis and checkpoint signaling. Whether these meiotic processes are equally dependent on axial element integrity has remained unclear. Here, we investigated this question in S.

Analysis of Meiotic Chromosome-Associated Protein Dynamics Using Conditional Expression in Budding Yeast.

The visualization of meiotic chromosomes and their associated protein structures in both wild-type and mutant cells adds valuable insight into the molecular pathways that underlie reproductive cell formation. Here we describe basic methodology for visualizing meiotic chromosomes in a long-standing model organism for investigating the molecular and cell biology of meiosis, the budding yeast, S. cerevisiae.

Genetic architecture and pleiotropy shape costs of Rps2-mediated resistance in Arabidopsis thaliana.

The mounting evidence that R genes incur large fitness costs raises a question: how can there be a 5-10% fitness reduction for all 149 R genes in the Arabidopsis thaliana genome? The R genes tested to date segregate for insertion-deletion (indel) polymorphisms where susceptible alleles are complete deletions. Since costs of resistance are measured as the differential fitness of isolines carrying resistant and susceptible alleles, indels reveal costs that may be masked when susceptible alleles are expressed. Rps2 segregates for two expressed clades of alleles, one resistant and one susceptible.

Synaptonemal Complex Proteins of Budding Yeast Define Reciprocal Roles in MutSγ-Mediated Crossover Formation.

During meiosis, crossover recombination creates attachments between homologous chromosomes that are essential for a precise reduction in chromosome ploidy. Many of the events that ultimately process DNA repair intermediates into crossovers during meiosis occur within the context of homologous chromosomes that are tightly aligned via a conserved structure called the synaptonemal complex (SC), but the functional relationship between SC and crossover recombination remains obscure. There exists a widespread correlation across organisms between the presence of SC proteins and successful crossing over, indicating that the SC or its building block components are procrossover factors .

Modulation of R-gene expression across environments.

Some environments are more conducive to pathogen growth than others, and, as a consequence, plants might be expected to invest more in resistance when pathogen growth is favored. Resistance (R-) genes in Arabidopsis thaliana have unusually extensive variation in basal expression when comparing the same R-gene among accessions collected from different environments. R-gene expression variation was characterized to explore whether R-gene expression is up-regulated in environments favoring pathogen proliferation and down-regulated when risks of infection are low; down-regulation would follow if costs of R-gene expression negatively impact plant fitness in the absence of disease.

Chromosome Synapsis Alleviates Mek1-Dependent Suppression of Meiotic DNA Repair.

Faithful meiotic chromosome segregation and fertility require meiotic recombination between homologous chromosomes rather than the equally available sister chromatid, a bias that in Saccharomyces cerevisiae depends on the meiotic kinase, Mek1. Mek1 is thought to mediate repair template bias by specifically suppressing sister-directed repair. Instead, we found that when Mek1 persists on closely paired (synapsed) homologues, DNA repair is severely delayed, suggesting that Mek1 suppresses any proximal repair template.