The phenotype of a phospholipase C (plc-1) mutant in a filamentous fungus, Neurospora crassa
| Autor: | Miranda S.H. Lorenti, Rachel Giblon, Roger R. Lew |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Hyphal tip growth
Genotype Mutant Nonsense mutation Hyphae Hyphal tip Biology Microbiology Fluorescence imaging Neurospora crassa Gene product Gene Knockout Techniques 03 medical and health sciences Phospholipase C Turgor Botany Genetics Tip growth Enzyme Inhibitors Genetic Association Studies 030304 developmental biology 0303 health sciences 030306 microbiology Wild type biology.organism_classification Electrophysiological Phenomena Cell biology Electrophysiology Phenotype Type C Phospholipases Mutation Calcium |
| Zdroj: | Fungal Genetics and Biology. 82:158-167 |
| ISSN: | 1087-1845 |
| Popis: | In the filamentous fungus Neurospora crassa, phospholipase C may play a role in hyphal extension at the growing tips as part of a growth-sensing mechanism that activates calcium release from internal stores to mediate continued expansion of the hyphal tip. One candidate for a tip-localized phospholipase C is PLC-1. We characterized morphology and growth characteristics of a knockout mutant (KO plc-1) and a RIP mutated strain (RIP plc-1) (missense mutations and a nonsense mutation render the gene product non-functional). Growth and hyphal cytology of wildtype and KO plc-1 were similar, but the RIP plc-1 mutant grew slower and exhibited abnormal membrane structures at the hyphal tip, imaged using the fluorescence dye FM4-64. To test for causes of the slower growth of the RIP plc-1 mutant, we examined its physiological poise compared to wildtype and the KO plc-1 mutant. The electrical properties of all three strains and the electrogenic contribution of the plasma membrane H+-ATPase (identified by cyanide inhibition) were the same. Responses to high osmolarity were also similar. However, the RIP plc-1 mutant had a significantly lower turgor, a possible cause of its slower growth. While growth of all three strains was inhibited by the phospholipase C inhibitor 3-nitrocoumarin, the RIP plc-1 mutant did not exhibit hyphal bursting after addition of the inhibitor, observed in both wildtype and the KO plc-1 mutant. Although the plc-1 gene is not obligatory for tip growth, the phenotype of the RIP plc-1 mutant – abnormal tip cytology, lower turgor and resistance to inhibitor-induced hyphal bursting – suggest it does play a role in tip growth. The expression of a dysfunctional plc-1 gene may cause a shift to alternative mechanism(s) of growth sensing in hyphal extension. |
| Databáze: | OpenAIRE |
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