Exo1 recruits Cdc5 polo kinase to MutLγ to ensure efficient meiotic crossover formation.

Crossovers generated during the repair of programmed meiotic double-strand breaks must be tightly regulated to promote accurate homolog segregation without deleterious outcomes, such as aneuploidy. The Mlh1-Mlh3 (MutLγ) endonuclease complex is critical for crossover resolution, which involves mechanistically unclear interplay between MutLγ and Exo1 and polo kinase Cdc5. Using budding yeast to gain temporal and genetic traction on crossover regulation, we find that MutLγ constitutively interacts with Exo1.

The preprophase band of microtubules controls the robustness of division orientation in plants.

Controlling cell division plane orientation is essential for morphogenesis in multicellular organisms. In plant cells, the future cortical division plane is marked before mitotic entry by the preprophase band (PPB). Here, we characterized an (TON1 Recruiting Motif) mutant that impairs PPB formation but does not affect interphase microtubules.

Concerted action of the MutLβ heterodimer and Mer3 helicase regulates the global extent of meiotic gene conversion.

Gene conversions resulting from meiotic recombination are critical in shaping genome diversification and evolution. How the extent of gene conversions is regulated is unknown. Here we show that the budding yeast mismatch repair related MutLβ complex, Mlh1-Mlh2, specifically interacts with the conserved meiotic Mer3 helicase, which recruits it to recombination hotspots, independently of mismatch recognition.

The kinesin AtPSS1 promotes synapsis and is required for proper crossover distribution in meiosis.

Meiotic crossovers (COs) shape genetic diversity by mixing homologous chromosomes at each generation. CO distribution is a highly regulated process. CO assurance forces the occurrence of at least one obligatory CO per chromosome pair, CO homeostasis smoothes out the number of COs when faced with variation in precursor number and CO interference keeps multiple COs away from each other along a chromosome.

A protein phosphatase 2A complex spatially controls plant cell division.

In the absence of cell migration, the orientation of cell divisions is crucial for body plan determination in plants. The position of the division plane in plant cells is set up premitotically via a transient cytoskeletal array, the preprophase band, which precisely delineates the cortical plane of division. Here we describe a protein complex that targets protein phosphatase 2A activity to microtubules, regulating the transition from the interphase to the premitotic microtubule array.

The Arabidopsis TRM1-TON1 interaction reveals a recruitment network common to plant cortical microtubule arrays and eukaryotic centrosomes.

Land plant cells assemble microtubule arrays without a conspicuous microtubule organizing center like a centrosome. In Arabidopsis thaliana, the TONNEAU1 (TON1) proteins, which share similarity with FOP, a human centrosomal protein, are essential for microtubule organization at the cortex. We have identified a novel superfamily of 34 proteins conserved in land plants, the TON1 Recruiting Motif (TRM) proteins, which share six short conserved motifs, including a TON1-interacting motif present in all TRMs.

The Ogura sterility-inducing protein forms a large complex without interfering with the oxidative phosphorylation components in rapeseed mitochondria.

The Ogura cytoplasmic male sterility causing protein, ORF138, was found to be part of a complex with an apparent size of over 750 kDa in the inner membrane of mitochondria of sterile plants. ORF138 did not colocalize with any of the oxidative phosphorylation complexes, nor did its presence modify their apparent size or amount, compared to samples from fertile isogenic plants. We attempted to detect potential proteins or nucleic acids that could be involved in the large ORF138 complex by 2D PAGE, immunoprecipitation and nuclease treatments of native extracts.

Mutations in three distinct loci cause resistance to peptide deformylase inhibitors in Bacillus subtilis.

Bacillus subtilis mutants with resistance against peptide deformylase inhibitors were isolated. All showed a bypass of the pathway through mutations in three genes required for formylation of Met-tRNA(fMet), fmt, folD, and glyA. glyA corresponds to a yet uncharacterized locus inducing resistance.

Structure-activity relationship analysis of the peptide deformylase inhibitor 5-bromo-1H-indole-3-acetohydroxamic acid.

The lead compound 5-bromoindolyl-3-acetohydroxamic acid (10) was recently identified as a potent inhibitor of bacterial peptide deformylases (PDFs). The synthesis and associated activities of new variants were investigated at position 5 to optimize the fit at the S1' subsite and at position 1 to improve both potency and antibacterial activity. A morphomimetic series, termed "reverse-indole" was synthesized.

Discovery and refinement of a new structural class of potent peptide deformylase inhibitors.

New classes of antibiotics are urgently needed to counter increasing levels of pathogen resistance. Peptide deformylase (PDF) was originally selected as a specific bacterial target, but a human homologue, the inhibition of which causes cell death, was recently discovered. We developed a dual-screening strategy for selecting highly effective compounds with low inhibition effect against human PDF.

Biochemical and functional characterization of ORF138, a mitochondrial protein responsible for Ogura cytoplasmic male sterility in Brassiceae.

In cytoplasmic male sterility (CMS), original mitochondrial genes contribute to sex determinism by provoking pollen abortion. The function of the encoded proteins remains unclear. We studied the ORF138 protein, responsible for the 'Ogura' CMS, which is both used in hybrid seed production and present in natural populations.