title: Microtubules are reversibly depolymerized in response to changing gaseous microenvironments withinAspergillus nidulansbiofilms.
abstract: How microtubules (MTs) are regulated during fungal biofilm formation is unknown. By tracking MT +end-binding proteins (+TIPS) inAspergillus nidulans, we find that MTs are regulated to depolymerize within forming fungal biofilms. During this process, EB1, dynein, and ClipA form transient fibrous and then bar-like structures, novel configurations for +TIPS. Cells also respond in an autonomous manner, with cells separated by a septum able to maintain different MT dynamics. Surprisingly, all cells with depolymerized MTs rapidly repolymerize their MTs after air exchange above the static culture medium of biofilms. Although the specific gasotransmitter for this biofilm response is not known, we find that addition of hydrogen sulfide gas to growing cells recapitulates all aspects of reversible MT depolymerization and transient formation of +TIPs bars. However, as biofilms mature, physical removal of part of the biofilm is required to promote MT repolymerization, which occurs at the new biofilm edge. We further show MT depolymerization within biofilms is regulated by the SrbA hypoxic transcription factor and that without SrbA, MTs are maintained as biofilms form. This reveals a new mode of MT regulation in response to changing gaseous biofilm microenvironments, which could contribute to the unique characteristics of fungal biofilms in medical and industrial settings.
authors.affiliation: Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210.|Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210.
authors.forename: Nandini
authors.initials: N
authors.lastname: Shukla
authors.affiliation: Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210.
authors.forename: Aysha H
authors.initials: AH
authors.lastname: Osmani
authors.affiliation: Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210 osmani.2@osu.edu.|Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Osmani
mesh_terms: D051339:Actin Depolymerizing Factors / Q000378:metabolism; D001233:Aspergillus nidulans / Q000378:metabolism / Q000502:physiology*; D018441:Biofilms / Q000254:growth & development*; D060833:Cellular Microenvironment / Q000502:physiology; D004398:Dyneins / Q000378:metabolism; D005740:Gases; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D058105:Polymerization
chemical_list: D051339:Actin Depolymerizing Factors; D005740:Gases; D008869:Microtubule-Associated Proteins; D004398:Dyneins