Biology subjects

Robles, P.

Publications and source records attributed to Robles, P..

4 recordsLinked to original sources

bioRxiv2022

GRAS-1 is a conserved novel regulator of early meiotic chromosome dynamics in C. elegans

Chromosome movements and licensing of synapsis must be tightly regulated during early meiosis to ensure accurate chromosome segregation and avoid aneuploidy, although how these steps are coordinated is not fully understood. Here we show that GRAS-1, the worm homolog of mammalian GRASP/Tamalin and CYTIP, coordinates early meiotic events with cytoskeletal forces outside the nucleus. GRAS-1 localizes close to the nuclear envelope (NE) in early prophase I and interacts with NE and cytoskeleton proteins. Delayed homologous chromosome pairing, synaptonemal complex (SC) assembly, and DNA double-strand break repair progression are partially rescued by the expression of human CYTIP in gras-1 mutants, supporting functional conservation. However, Tamalin, Cytip double knockout mice do not exhibit obvious fertility or meiotic defects, suggesting evolutionary differences between mammals. gras-1 mutants show accelerated chromosome movement during early prophase I, implicating GRAS-1 in regulating chromosome dynamics. GRAS-1-mediated regulation of chromosome movement is DHC-1-dependent, placing it acting within the LINC-controlled pathway, and depends on GRAS-1 phosphorylation at a C-terminal S/T cluster. We propose that GRAS-1 serves as a scaffold for a multi-protein complex coordinating the early steps of homology search and licensing of SC assembly by regulating the pace of chromosome movement in early prophase I.

cell biology↗

bioRxiv2022

The Arabidopsis ATP-Binding Cassette E protein ABCE2 is a conserved component of the translation machinery

O_LIATP-Binding Cassette E (ABCE) proteins dissociate cytoplasmic ribosomes after translation terminates, and contribute to ribosome recycling, thus linking translation termination to initiation. This function has been demonstrated to be essential in animals, fungi, and archaea, but remains unexplored in plants. C_LIO_LIIn most species, ABCE is encoded by a single-copy gene; by contrast, Arabidopsis thaliana has two ABCE paralogs, of which ABCE2 seems to conserve the ancestral function. We isolated apiculata7-1 (api7-1), a viable, hypomorphic allele of ABCE2,which has a pleiotropic morphological phenotype reminiscent of mutations affecting ribosome biogenesis factors and ribosomal proteins. We also studied api7-2, a null, recessive lethal allele of ABCE2. C_LIO_LICo-immunoprecipitation experiments showed that ABCE2 physically interacts with components of the translation machinery. An RNA-seq study of the api7-1 mutant showed increased responses to iron and sulfur starvation. We also found increased transcript levels of genes related to auxin signaling and metabolism. C_LIO_LIOur results support a conserved role for ABCE proteins in ribosome recycling in plants, as previously shown for the animal, fungal, and archaeal lineages. In plants, the ABCE2 protein seems important for general growth and vascular development, likely due to an indirect effect through auxin metabolism. C_LI

plant biology↗

bioRxiv2020

Chromatin-associated effectors of energy-sensing pathways mediate intergenerational effects

Environmental stimuli experienced by the parental generation influence the phenotype of subsequent generations. The effects of these stimuli on the parental generation may be passed through the germline, but the mechanisms of this non-Mendelian type of inheritance are poorly known. Here we show that modulation of nutrient-sensing pathways in the parental generation of a nematode (Auanema freiburgensis) regulates phenotypic plasticity of its offspring. In response to pheromones, AMP-activated protein kinase (AMPK), mechanistic target of rapamycin complex 1 (mTORC1) and insulin signaling regulate stress resistance and sex determination across a generation. The effectors of these pathways are closely associated with the chromatin and their regulation affects the acetylation chromatin status in the germline. These results suggest that highly conserved metabolic sensors regulate phenotypic plasticity by changing the epigenetic status of the germline.

developmental biology↗

bioRxiv2018

Sensory neurons control heritable adaptation to stress through germline reprogramming

Maternal neuronal signaling has been reported to program adaptive changes in offspring physiology in diverse organisms [1, 2]. However, the mechanisms for the inheritance of adaptive maternal effects through the germline are largely unknown. In the nematode Auanema freiburgensis, stress-resistance and sex of the offspring depend on environmental cues experienced by the mother. Maternal sensing of high population densities results in the production of stress-resistant larvae (dauers) that develop into hermaphrodites. Ablation of the maternal ASH chemosensory neurons results only in non-dauer offspring that develop into males or females. High population densities correlate with changes in the methylation status of H3K4 and H3K9 in the maternal germline. Inhibition of JMJD histone demethylases prevents mothers from producing dauers and hermaphrodite offspring in high-density conditions. Our results demonstrate a case of soma-to-germline transmission of environmental information that influences the phenotype of the following generation through changes in histone modifications of the maternal germline.\n\nHighlightsO_LIHigh population density leads to the production of hermaphrodite offspring.\nC_LIO_LIThe ASH neuron in the hermaphrodite mother senses population density.\nC_LIO_LIHistone modifications in the maternal germline correlate with the sex of offspring.\nC_LIO_LIInhibition of histone demethylases results in female offspring in all conditions.\nC_LI

developmental biology↗