Conditional expression of the phospho8208;transmitter gene ypdA and the interaction of YpdA with response regulators in Aspergillus nidulans.

Ref ID: 18499

Author:

Yura Midorikawa,
Daisuke Hagiwara,
Mayumi Nakayama,
Kei Yoshimi,
Fumihiko Hasegawa,
Keietsu Abe

Author address:

Grad. Sch. Agric. Sci. Tohoku Univ  
MMRC, Univ. of Chiba  
NICHe, Tohiku Univ  
Grad. Sch. Agric. Sci. & NICHe,
Tohoku Univ

Full conference title:

11 th European Conference on Fungal Genetics

Abstract:

Eukaryotic histidine8208;to8208;aspartate (His8208;Asp) phosphorelay systems consist of three types of common signal
transducers: His8208;kinase (HK), a response regulator (RR), and a histidine8208;containing phosphotransfer intermediate
(HPt). In general, HPt acts as an intermediate between HK and RR and is indispensable for inducing appropriate
responses to environmental stresses through His8208;Asp phosphotransfer signaling. Although HPt is thought to be
essential among Aspergillus species, the molecular mechanism underlying the HPtA essentiality remains unclear. In
the present study, we constructed Aspergillus nidulans mutant in which expression of the HPt gene ypdA is
conditionally regulated under the control of the A. nidulans alcA promoter (CypdA strain). When CypdA was
cultured in CD medium (repressed condition), the transcript level of the ypdA gene was decreased to 5% that of
the wild type (ABPU1). In CD medium, CypdA showed remarkable growth retardation and formed abnormal
hyphae, suggesting that YpdA is an essential component. Downregulation of ypdA expression resulted in induction
of the catA and gfdB genes, which are upregulated downstream of the active HogA mitogen8208;activated protein
kinase (MAPK) cascade. We then constructed mutant strain from CypdA by deleting the response regulator gene
srrA (CypdA/916;srrA). When ypdA was downregulated, CypdA/916;srrA unexpectedly showed more severe growth
retardation than the parent CypdA. We are also trying to isolate a mutant from CypdA by deleting another
response regulator gene sskA. Here, we discuss two8208;component signaling under the inhibitory conditions of
signaling between YpdA and response regulators.

Abstract Number: PR7.12

Conference Year: 2012

Link to conference website: http://www.ecfg.info/images/Abstract_Book_Electronic.pdf

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