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Tip‐to‐nucleus migration dynamics of the asexual development regulator FlbB in vegetative cells
Author(s) -
HerreroGarcia Erika,
PerezdeNanclaresArregi Elixabet,
Cortese Marc S.,
MarkinaIñarrairaegui Ane,
OiartzabalArano Elixabet,
Etxebeste Oier,
Ugalde Unai,
Espeso Eduardo A.
Publication year - 2015
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/mmi.13156
Subject(s) - biology , transcription factor , microbiology and biotechnology , nuclear transport , nucleus , nuclear localization sequence , cell nucleus , nuclear protein , genetics , gene
Summary In A spergillus nidulans , asexual differentiation requires the presence of the transcription factor FlbB at the cell tip and apical nuclei. Understanding the relationship between these two pools is crucial for elucidating the biochemical processes mediating conidia production. Tip‐to‐nucleus communication was demonstrated by photo‐convertible FlbB :: D endra2 visualization. Tip localization of FlbB depends on C ys382 in the C ‐terminus and the b ZIP DNA ‐binding domain in the N ‐terminus. FlbE , a critical FlbB interactor, binds the b ZIP domain. Furthermore, the absence of FlbE results in loss of tip localization but not nuclear accumulation. flb E deletion also abrogates transcriptional activity indicating that FlbB gains transcriptional competence from interactions with FlbE at the tip. Finally, a bipartite nuclear localization signal is required for nuclear localization of FlbB . Those motifs of FlbB may play various roles in the sequence of events necessary for the distribution and activation of this transcriptionally active developmental factor. The tip accumulation, FlbE ‐dependent activation, transport and nuclear import sketch out a process of relaying an environmentally triggered signal from the tip to the nuclei. As the first known instance of transcription factor‐mediated tip‐to‐nucleus communication in filamentous fungi, this provides a general framework for analyses focused on elucidating the set of molecular mechanisms coupling apical signals to transcriptional events.