Biology subjects

Vopalensky, P.

Publications and source records attributed to Vopalensky, P..

2 recordsLinked to original sources

bioRxiv2024

Exploring RNA modifications in infectious non-coding circular RNAs

Viroids, small circular non-coding RNAs, act as infectious pathogens in higher plants, demonstrating high stability despite consisting solely of naked RNA. Their dependence of replication on host machinery poses the question of whether RNA modifications play a role in viroid biology. Here, we explore RNA modifications in the avocado sunblotch viroid (ASBVd) and the citrus exocortis viroid (CEVd), representative members of viroids replicating in chloroplasts and the nucleus, respectively, using LC-MS and Oxford Nanopore Technology (ONT) direct RNA sequencing. Although no modification was detected in ASBVd, CEVd contained approximately one m6 A per RNA molecule. ONT sequencing predicted three m6 A positions. Employing orthogonal SELECT method, we confirmed m6 A in two positions A353 and A360, which are highly conserved among CEVd variants. These postitions are located in the left terminal region of the CEVd rod-like structure where likely RNA Pol II and and TFIIIA-7ZF bind, thus suggesting potential biological role of methylation in viroid replication. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=125 SRC="FIGDIR/small/584625v2_ufig1.gif" ALT="Figure 1"> View larger version (19K): org.highwire.dtl.DTLVardef@1dfe2f1org.highwire.dtl.DTLVardef@1ac717eorg.highwire.dtl.DTLVardef@4f1563org.highwire.dtl.DTLVardef@542d9_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2018

From spiral cleavage to bilateral symmetry: The developmental cell lineage of the annelid brain

The spiral cleavage pattern is characteristic for Spiralia (Lophotrochozoa), a large assembly of marine invertebrates. In most cases, spiral cleavage produces freely swimming, trochophora-type larvae with a simple nervous system that controls ciliary locomotion. These larvae acquire bilateral symmetry, as manifested for example in the larval brain. The transition from the rotational symmetry of spiral cleavage into the bilateral adult body has not yet been understood. Here, we present the developmental cell lineage of the brain of the annelid Platynereis dumerilii from the zygote until the mid-trochophore stage (~30 hpf), in combination with a gene expression atlas for several embryonic and larval stages. Comparison of multiple embryos reveals a highly stereotypical development and an invariant cell lineage of the differentiated cell types. In addition, we observe a fundamental subdivision of the larval brain into a highly proliferative dorsolateral region and an early differentiating ventromedial region that gives rise to the apical nervous system. The transition from rotational to bilateral symmetry progresses gradually from the lateral to the central regions. Strikingly, the spiral-to-bilateral transition does not involve extensive cell migration. Rather, corresponding cells in different spiral quadrants acquire highly divergent identities in line with their bilateral position.

developmental biology↗