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Functional stratification of the Spitzenkörper of Neurospora crassa
Author(s) -
Verdín Jorge,
BartnickiGarcia Salomon,
Riquelme Meritxell
Publication year - 2009
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2009.06917.x
Subject(s) - neurospora crassa , biology , crassa , chitin , hypha , apex (geometry) , chitin synthase , cell wall , microbiology and biotechnology , population , vesicle , biochemistry , biophysics , anatomy , chitosan , gene , demography , membrane , sociology , mutant
Summary GS‐1 (ncu04189) is a protein required for the synthesis of β‐1,3‐glucan in Neurospora crassa . As chitin, β‐1,3‐glucan is a morphogenetically relevant component of the fungal cell wall. Previously, we showed that chitin synthases are delivered to the growing hyphal tip of N. crassa by secretory microvesicles that follow an unconventional route and accumulate in the core of the Spitzenkörper (Spk). Tagged with the green fluorescent protein (GFP), GS‐1 accumulated in the hyphal apex forming a dynamic and pleomorphic ring‐like structure (‘Spitzenring’) that corresponded to the Spk outer macrovesicular stratum and surrounded the inner core of chitin synthase‐containing microvesicles. TIRF microscopy revealed that GS‐1‐GFP reached the hyphal apex as a population of heterogeneous‐size particles that moved along defined paths. On sucrose density gradients, GS‐1‐associated particles mainly sedimented in a high density range 1.1272–1.2124 g ml −1 . Clearly, GS‐1 and chitin synthases of N. crassa are contained in two different types of secretory vesicles that accumulate in different strata of the Spk, a differentiation presumably related to the spatial control of cell‐wall synthesis.