An official website of the United States government
Abstract In Neurospora crassa, expression from an unpaired gene is suppressed by a mechanism known as meiotic silencing by unpaired DNA (MSUD). MSUD utilizes common RNA interference (RNAi) factors to silence target mRNAs. Here, we report that Neurospora CAR-1 and CGH-1, homologs of two Caenorhabditis elegans RNA granule components, are involved in MSUD. These fungal proteins are found in the perinuclear region and P-bodies, much like their worm counterparts. They interact with components of the meiotic silencing complex (MSC), including the SMS-2 Argonaute. This is the first time MSUD has been linked to RNA granule proteins.
more »
« less
Suppressors of Meiotic Silencing by Unpaired DNA
Meiotic silencing by unpaired DNA (MSUD) is a gene silencing process that occurs within meiotic cells of Neurospora crassa and other fungi. We have previously developed a high-throughput screen to identify suppressors of this silencing pathway. Here, a list of MSUD suppressor candidates from a single pass of the first 84 plates of the Neurospora knockout library is provided.
more »
« less
- Award ID(s):
- 1715534
- PAR ID:
- 10092105
- Date Published:
- Journal Name:
- Non-Coding RNA
- Volume:
- 5
- Issue:
- 1
- ISSN:
- 2311-553X
- Page Range / eLocation ID:
- 14
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
null (Ed.)Abstract In the filamentous fungus Neurospora crassa, genes unpaired during meiosis are silenced by a process known as meiotic silencing by unpaired DNA (MSUD). MSUD utilizes common RNA interference (RNAi) proteins, such as Dicer and Argonaute, to target homologous mRNAs for silencing. Previously, we demonstrated that nuclear cap-binding proteins NCBP1 and NCBP2 are involved in MSUD. We report here that SAD-8, a protein similar to human NCBP3, also mediates silencing. Although SAD-8 is not essential for either vegetative or sexual development, it is required for MSUD. SAD-8 localizes predominantly in the nucleus and interacts with both NCBP1 and NCBP2. Similar to NCBP1 and NCBP2, SAD-8 interacts with a component (Argonaute) of the perinuclear meiotic silencing complex (MSC), further implicating the involvement of cap-binding proteins in silencing.more » « less
-
Abstract During the sexual phase of Neurospora crassa, unpaired genes are subject to a silencing mechanism known as meiotic silencing by unpaired DNA (MSUD). MSUD targets the transcripts of an unpaired gene and utilizes typical RNA interference factors for its process. Using a reverse genetic screen, we have identified a meiotic silencing gene called sad-9, which encodes a DEAD-box RNA helicase. While not essential for vegetative growth, SAD-9 plays a crucial role in both sexual development and MSUD. Our results suggest that SAD-9, with the help of the SAD-2 scaffold protein, recruits the SMS-2 Argonaute to the perinuclear region, the center of MSUD activity.more » « less
-
null (Ed.)Meiotic drive elements cause their own preferential transmission following meiosis. In fungi, this phenomenon takes the shape of spore killing, and in the filamentous ascomycete Neurospora sitophila , the Sk-1 spore killer element is found in many natural populations. In this study, we identify the gene responsible for spore killing in Sk-1 by generating both long- and short-read genomic data and by using these data to perform a genome-wide association test. We name this gene Spk-1 . Through molecular dissection, we show that a single 405-nt-long open reading frame generates a product that both acts as a poison capable of killing sibling spores and as an antidote that rescues spores that produce it. By phylogenetic analysis, we demonstrate that the gene has likely been introgressed from the closely related species Neurospora hispaniola , and we identify three subclades of N. sitophila , one where Sk-1 is fixed, another where Sk-1 is absent, and a third where both killer and sensitive strain are found. Finally, we show that spore killing can be suppressed through an RNA interference-based genome defense pathway known as meiotic silencing by unpaired DNA. Spk-1 is not related to other known meiotic drive genes, and similar sequences are only found within Neurospora . These results shed light on the diversity of genes capable of causing meiotic drive, their origin and evolution, and their interaction with the host genome.more » « less
-
Meiotic drive elements, sometimes called selfish genes, are genetic elements that are passed on to their offspring more favorably than other genes. Meiotic drive elements have been observed in many organisms, including fungi of the Neurospora genus. Three different meiotic drive elements, called Spore killers, have been identified in Neurospora fungi. One of these Spore killers is called Spore killer 3 (Sk-3), and the molecular mechanism by which Sk-3 acts as a meiotic drive element is poorly understood. Previous work has identified a genetic locus within Sk-3 that may control spore killing. In this thesis, I investigate an interval of DNA within this locus called v375. Through gene deletion and spore killing assays, I show that deletion of v375 disrupts Sk-3-based spore killing in N. crassa. Possible explanations for why interval v375 is required for spore killing by Sk-3 are discussed.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/ncrna5010014
