In plants, RNA interference (RNAi) plays a pivotal role in growth and development, and responses to environmental inputs, including pathogen attack. The intercellular and systemic trafficking of small interfering RNA (siRNA)/microRNA (miRNA) is a central component in this regulatory pathway. Currently, little is known with regards to the molecular agents involved in the movement of these si/miRNAs. To address this situation, we employed a biochemical approach to identify and characterize a conserved SMALL RNA-BINDING PROTEIN 1 (SRBP1) family that mediates non-cell-autonomous small RNA (sRNA) trafficking. In Arabidopsis, AtSRBP1 is a glycine-rich (GR) RNA-binding protein, also known as AtGRP7, which we show binds single-stranded siRNA. A viral vector, Zucchini yellow mosaic virus (ZYMV), was employed to functionally characterized the AtSRBP1-4 (AtGRP7/2/4/8) RNA recognition motif and GR domains. Cellular-based studies revealed the GR domain as being necessary and sufficient for SRBP1 cell-to-cell movement. Taken together, our findings provide a foundation for future research into the mechanism and function of mobile sRNA signaling agents in plants.
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http://dx.doi.org/10.1016/j.molp.2019.12.001 | DOI Listing |
Mol Biol Evol
January 2025
Center for Genomics and Systems Biology, Department of Biology, New York University.
Copy-number variants (CNVs) are an important class of genetic variation that can mediate rapid adaptive evolution. Whereas CNVs can increase the relative fitness of the organism, they can also incur a cost due to the associated increased gene expression and repetitive DNA. We previously evolved populations of Saccharomyces cerevisiae over hundreds of generations in glutamine-limited (Gln-) chemostats and observed the recurrent evolution of CNVs at the GAP1 locus.
View Article and Find Full Text PDFBiochemistry
January 2025
Department of Developmental Biology and Genetics, Indian Institute of Science, Bengaluru 560012, India.
Eukaryotic Initiation Factor 4 (eIF4) is a group of factors that activates mRNA for translation and recruit 43S preinitiation complex (PIC) to the mRNA 5' end, forming the 48S PIC. The eIF4 factors include mRNA 5' cap-binding protein eIF4E, ATP-dependent RNA helicase eIF4A, and scaffold protein eIF4G, which anchors eIF4A and eIF4E. Another eIF4 factor, eIF4B, stimulates the RNA helicase activity of eIF4A and facilitates mRNA recruitment.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Max Perutz Labs, Vienna Biocenter Campus, Vienna 1030, Austria.
RNA G-quadruplexes (rG4s), the four-stranded structures formed by guanine-rich RNA sequences, are recognized by regions in RNA-binding proteins (RBPs) that are enriched in arginine-glycine repeats (RGG motifs). Importantly, arginine and glycine are encoded by guanine-rich codons, suggesting that some RGG motifs may both be encoded by and interact with rG4s in autogenous messenger RNAs (mRNAs). By analyzing transcriptome-wide rG4 datasets, we show that hundreds of RGG motifs in humans are at least partly encoded by rG4s, with an increased incidence for longer RGG motifs (~10 or more residues).
View Article and Find Full Text PDFCell Mol Life Sci
January 2025
School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong.
C1orf115 has been identified in high-throughput screens as a regulator of multidrug resistance possibly mediated through an interaction with ATP-dependent membrane transporter ABCB1. Here we show that C1orf115 not only shares structural similarities with FACI/C11orf86 to interact with clathrin adaptors to undergo endocytosis, but also induces ABCA1 transcription to promote cholesterol efflux. C1orf115 consists of an N-terminal intrinsically disordered region and a C-terminal α-helix.
View Article and Find Full Text PDFJ Chem Inf Model
January 2025
Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, 600036 Tamil Nadu, India.
Interactions between proteins and RNAs are essential for the proper functioning of cells, and mutations in these molecules may lead to diseases. These protein mutations alter the strength of interactions between the protein and RNA, generally described as binding affinity (Δ). Hence, the affinity change upon mutation (ΔΔ) is an important parameter for understanding the effect of mutations in protein-RNA complexes.
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