Biology subjects

Amom, P.

Publications and source records attributed to Amom, P..

4 recordsLinked to original sources

bioRxiv2025

Modulating inter-mitochondrial contacts to increase membrane potential for mitigating blue light damage

Mitochondrial membrane potential (MMP) is essential for mitochondrial functions, yet current methods for modulating MMP lack precise spatial and temporal control. Here, we present an optogenetic system that enables reversible formation of inter-mitochondrial contacts (mito-contacts) with high spatiotemporal precision. Blue light stimulation induces rapid formation of mito-contacts, which fully dissipate upon cessation of illumination. These light-induced mito-contacts can enhance MMP, leading to increased ATP production under stress conditions. Moreover, in human retinal cells and C. elegans, high MMP induced by mito-contacts alleviates the deleterious effects of prolonged blue light exposure, restoring energy metabolism and extending organismal lifespan. This optogenetic approach provides a powerful tool for modulating MMP and offers potential therapeutic applications for diseases linked to mitochondrial dysfunction.

biophysics↗

bioRxiv2024

Vitamin B12 partially rescues embryonic cell migration defects in C. elegans ephrin mutants by improving both propionic acid breakdown and one-carbon cycle metabolic pathways

Successful cell migration followed by tissue fusion is required for organogenesis in a number of tissues, many of which are susceptible to gene-environment interactions that can result in congenital anomalies. In C. elegans embryogenesis, one such event is the closure of the ventral cleft, which must occur as the first step in morphogenesis, otherwise embryos arrest; this process depends on ephrin signaling, but no single gene mutation is fully penetrant embryonic lethal. We exposed hermaphrodites mutant for vab-1, the C. elegans ephrin receptor, to various environmental conditions and found that vitamin B12 supplementation could partially rescue the embryonic lethality of multiple alleles from 40% survival to 63% survival. Analysis of vab-1 mutant phenotypes showed that vitamin B12 reduced the frequency of ventral cleft closure failure by promoting more normal cell positions and increased migration by the precursor cells of those that adhere to close the cleft. We found that vitamin B12 partially rescued the embryonic lethality of other ephrin pathway mutants, but not mutants that have ventral cleft defects due to cell adhesion or cell fate defects. We found that rescue by vitamin B12 depends on its functions in both mitochondrial propionic acid breakdown and the one-carbon cycle, and that antioxidant treatment can also partially rescue ephrin pathway mutants. These results are distinct from the larval response to vitamin B12, which depends only on the one-carbon cycle, emphasizing the unique metabolism of embryos and particularly the metabolic needs of migrating cells. Overall, our findings highlight the C. elegans embryo a model system to investigate gene-environment interactions and developmental metabolism.

developmental biology↗

bioRxiv2021

Members of the ELMOD protein family specify formation of distinct aperture domains on the Arabidopsis pollen surface

Pollen apertures, the characteristic gaps in pollen wall exine, have emerged as a model for studying the formation of distinct plasma-membrane domains. In each species, aperture number, position, and morphology are typically fixed; across species they vary widely. During pollen development certain plasma-membrane domains attract specific proteins and lipids and become protected from exine deposition, developing into apertures. However, how these aperture domains are selected is unknown. Here, we demonstrate that patterns of aperture domains in Arabidopsis are controlled by the members of the ancient ELMOD protein family, which, although important in animals, has not been studied in plants. We show that two members of this family, MACARON (MCR) and ELMOD_A, act upstream of the previously discovered aperture proteins and that their expression levels influence the number of aperture domains that form on the surface of developing pollen grains. We also show that a third ELMOD family member, ELMOD_E, can interfere with MCR and ELMOD_A activities, changing aperture morphology and producing new aperture patterns. Our findings reveal key players controlling early steps in aperture domain formation, identify residues important for their function, and open new avenues for investigating how diversity of aperture patterns in nature is achieved.

plant biology↗

bioRxiv2021

The anterior Hox gene ceh-13 and elt-1/GATA activate the posterior Hox genes nob-1 and php-3 to specify posterior lineages in the C. elegans embryo

Hox transcription factors play a conserved role in specifying positional identity during animal development, with posterior Hox genes typically repressing the expression of more anterior Hox genes. Here, we dissect the regulation of the posterior Hox genes nob-1 and php-3 in the nematode C. elegans. We show that nob-1 and php-3 are co-expressed in gastrulation-stage embryos in cells that previously expressed the anterior Hox gene ceh-13. This expression is controlled by several partially redundant transcriptional enhancers. These enhancers require ceh-13 for expression, providing a striking example of an anterior Hox gene positively regulating a posterior Hox gene. Several other regulators also act positively through nob-1/php-3 enhancers, including elt-1/GATA, ceh-20/ceh-40/Pbx, unc-62/Meis, pop-1/TCF, ceh-36/Otx and unc-30/Pitx. We identified defects in both cell position and cell division patterns in ceh-13 and nob-1;php-3 mutants, suggesting that these factors regulate lineage identity in addition to positional identity. Together, our results highlight the complexity and flexibility of Hox gene regulation and function and the ability of developmental transcription factors to regulate different targets in different stages of development. Author SummaryHox genes are critical for head-to-tail patterning during embryonic development in all animals. Here we examine the factors that are necessary to turn on two posterior Hox genes, nob-1 and php-3, in the nematode worm, C. elegans. We identified six new transcription factors and three enhancer regions of DNA that can activate expression of nob-1/php-3. Unexpectedly, these activating transcription factors included ceh-13, an anterior Hox gene, and elt-1, a regulator of skin development that is briefly expressed in many cells that do not adopt skin fates, including the cells that express nob-1. Furthermore, the cellular defects we observed in ceh-13 and nob- 1;php-3 mutant embryos indicate that the early embryonic functions of these Hox genes help determine the identity of cells as well as their position within the embryo. Our findings identify new roles for Hox genes in C. elegans and emphasize the ability of transcription factors to contribute to the diversification of cell types and the adoption of specific cell types at different phases of embryonic development.

genetics↗