The GUL-1 Protein Binds Multiple RNAs Involved in Cell Wall Remodeling and Affects the MAK-1 Pathway in Neurospora crassa

Abstract

The Neurospora crassa GUL-1 is part of the COT-1 pathway, which plays key roles in regulating polar hyphal growth and cell wall remodeling. We show that GUL-1 is a bona fide RNA-binding protein (RBP) that can associate with 828 “core” mRNA species. When cell wall integrity (CWI) is challenged, expression of over 25% of genomic RNA species are modulated (2,628 mRNAs, including the GUL-1 mRNA). GUL-1 binds mRNAs of genes related to translation, cell wall remodeling, circadian clock, endoplasmic reticulum (ER), as well as CWI and MAPK pathway components. GUL-1 interacts with over 100 different proteins, including stress-granule and P-body proteins, ER components and components of the MAPK, COT-1, and STRIPAK complexes. Several additional RBPs were also shown to physically interact with GUL-1. Under stress conditions, GUL-1 can localize to the ER and affect the CWI pathway—evident via altered phosphorylation levels of MAK-1, interaction with mak-1 transcript, and involvement in the expression level of the transcription factor adv-1. We conclude that GUL-1 functions in multiple cellular processes, including the regulation of cell wall remodeling, via a mechanism associated with the MAK-1 pathway and stress-response.

Lineage-specific genes are clustered with allorecognition loci and respond to G × E factors regulating the switch from asexual to sexual reproduction inNeurospora

“…Their expression decreased after protoperithecia. NCU00176 was reported as one of the eight Neurospora orphan genes that were among the 300 down-regulated hypothetical proteins in the gul-1 knockout mutant (Herold et al 2019), and GUL-1 plays multiple roles in N. crassa hyphal morphology development (Herold et al 2021). We also confirmed increased pigment production in NCU00485 and dense and slow growth in NCU00491 and 016223 at 37 C.…”

Differential Expression of Cell Wall Remodeling Genes Is Part of the Dynamic Phase-Specific Transcriptional Program of Conidial Germination of Trichoderma asperelloides

“…RNA was isolated from T. asperelloides cultures after freezing in liquid nitrogen and grinding to a powder using a mortar and pestle, using the TRIzol reagent and the 1- Bromo-3-chloropropane (BCP, Sigma Aldrich) method, as previously described [ 45 ]. RNA samples were further purified with the RNA Clean and ConcentratorTM-5 kit (Zymo Research, Irvine, CA, USA) and treated with DNase (RNase-Free DNase Set, Qiagen, Hilden, Germany) according to the manufacturer’s instructions.…”

Unlocking the magic in mycelium: Using synthetic biology to optimize filamentous fungi for biomanufacturing and sustainability

“…A shortened mycelial phenotype is often coincident with hyper-branching mutants, which allows for high-density, low-viscosity cultures – ideal for highly-productive fermentation [ 278 ]. The COT-1 pathway plays a key role in cell-wall remodeling, cell differentiation, and polarization in filamentous fungi [ 279 , 280 ]. A key mediator of cell-wall remodeling within the COT-1 pathway, gul1 , was disrupted in strains of Neurospora crassa leading to increased protein secretion (25%), increased -glucosidase activity (56%), and markedly reduced medium viscosity [ [278] , [279] , [280] ].…”

“…The COT-1 pathway plays a key role in cell-wall remodeling, cell differentiation, and polarization in filamentous fungi [ 279 , 280 ]. A key mediator of cell-wall remodeling within the COT-1 pathway, gul1 , was disrupted in strains of Neurospora crassa leading to increased protein secretion (25%), increased -glucosidase activity (56%), and markedly reduced medium viscosity [ [278] , [279] , [280] ]. Another interesting target is the Rho GTPase RacA, involved in actin polymerization at the mycelial tip.…”