Ambient pH signaling regulates expression of the serine protease gene (spr1) in pine wilt nematode-trapping fungus, Monacrosporium megalosporum.
We have cloned and characterized spr1, a putative serine protease gene, from a nematode-trapping fungus, Monacrosporium megalosporum. The gene was present as a single copy in the genome. The predicted protein sequence of spr1 is homologous to the putative cuticle-degrading serine proteases PII and Azo1 from the nematode-trapping fungus, Arthrobotrys oligospora. In the 5' untranslated region near the initiation codon, consensus sequences to an AreA binding site, a well-known mediator of nitrogen metabolite repression in the fungus Aspergillus nidulans, a CreA binding site, a carbon response regulator in A. nidulans, and a PacC binding site, a transcription factor that responds to ambient pH signals in A. nidulans were found. However, spr1 was not regulated by carbon or nitrogen source, and exogenous protein did not induce expression of spr1. The transcription of the spr1 gene of this fungus was significantly affected by ambient pH. Based on RT-PCR, the product of the spr1 gene was not transcribed at pH 4, whereas under alkaline conditions such as pH 8 and 9, the spr1 gene was transcribed well. These results indicate that the spr1 gene is controlled only by a PacC homologue. Moreover, the expression profile of the spr1 gene corresponded with the pH-dependent physiology of this fungus.
Kanda
Satoshi
S
Department of Bioresource Development, Hiroshima Prefectural University, Shobara-shi, Hiroshima, Japan.
Aimi
Tadanori
T
Kano
Sanae
S
Ishihara
Shinji
S
Kitamoto
Yutaka
Y
Morinaga
Tsutomu
T
D000595:Amino Acid Sequence; D000818:Animals; D005658:Fungi / Q000201:enzymology / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009348:Nematoda / Q000382:microbiology*; D028223:Pinus / Q000469:parasitology; D010935:Plant Diseases / Q000469:parasitology; D012697:Serine Endopeptidases / Q000235:genetics*
D012697:Serine Endopeptidases