Biology subjects

Juarez-Gonzalez, V. T.

Publications and source records attributed to Juarez-Gonzalez, V. T..

3 recordsLinked to original sources

bioRxiv2025

Developmentally-controlled generation of tRNA halves facilitates translational repression during sexual reproduction

The role of transfer RNAs (tRNAs) as mediators between the genetic code and protein synthesis is well established. In parallel, tRNAs can generate different types of functional small RNAs (sRNAs) that accumulate during stress and certain developmental processes across diverse organisms. Interestingly, this class of sRNAs (termed tRNA-derived sRNAs, tsRNAs) accumulate in the male gamete of mammals, insects, and plants but their role in these reproductive cells is unclear. Here, we determine the molecular pathway of tsRNA biogenesis in the plant male gamete-containing structure (the pollen grain) and identify their role in mediating the characteristic translational repression taking place in this tissue. Our data demonstrates that male-accumulating tsRNAs are generated by a cell-controlled pathway to aid in mediating reproductive translational repression and that their accumulation is key to ensuring the proper function of the pollen grain.

plant biology↗

bioRxiv2023

Hop stunt viroid infection alters host heterochromatin

Viroids are pathogenic non-coding RNAs that completely rely on their host molecular machinery to accomplish their life cycle. Several interactions between viroids and their host molecular machinery have been identified, including an interference with epigenetic mechanisms such as DNA methylation. Despite this, whether viroids influence changes in other epigenetic marks such as histone modifications remained unknown. Epigenetic regulation is particularly important during pathogenesis processes because it might be a key regulator of the dynamism of the defense response. Here we have analyzed the changes taking place in Cucumis sativus facultative and constitutive heterochromatin during hop stunt viroid (HSVd) infection using chromatin immunoprecipitation (ChIP) of the two main heterochromatic marks: H3K9me2 and H3K27me3. We find that HSVd infection is associated with changes in both H3K27me3 and H3K9me2, with a tendency to decrease the levels of repressive epigenetic marks through infection progression. These epigenetic changes are connected to the transcriptional regulation of their expected targets, genes and transposable elements. Indeed, several genes related to the defense response are targets of both epigenetic marks. Our results highlight another host regulatory mechanism affected by viroid infection, providing further information about the complexity of the multiple layers of interactions between pathogens/viroids and hosts/plants.

plant biology↗

bioRxiv2023

Heterochromatin re-organization associated with the transcriptional reprogramming under viral infection in Arabidopsis

Epigenetic mechanisms are key regulators of genomic integrity and genic expression. Emerging evidence shows that epigenetic regulation is an important component of the transcriptional reprogramming during stress. Despite this, the overall stress-induced reprogramming of the different epigenetic marks and their targets are unknown. Here, we uncovered multiple epigenetic changes taking place during viral infection in Arabidopsis thaliana and their connection with gene expression. We find that cucumber mosaic virus (CMV) infection induces an overall reorganization of the repressive epigenetic marks H3K9me2, H3K27me3, and DNA methylation, which interact between them and are dynamic during infection. Overall, these epigenetic changes are involved in the reprogramming of the transcriptional program to adapt to the biotic stress, and might ensure genome stability through the transcriptional control of transposable elements (TEs). Mechanistically, we demonstrate that the catalytic component of the Polycomb Repressive Complex 2 (PRC2) CURLY LEAF (CLF) mediates the transcriptional repression of genes gaining H3K27me3 during viral infection and that mutants on that component induce resistance against CMV. Altogether, our results provide a complete picture of the epigenetic changes that occur during biotic stress and exemplify the overall dynamism of epigenetic regulation in eukaryotic organisms.

plant biology↗