Comparative Biochemistry and Physiology Part B 134 (2003) 161–170 1096-4959/03/$ - see front matter  2002 Elsevier Science Inc. All rights reserved. PII:S1096-4959 Ž 02 . 00188-4 Expression of protein phosphatase 1 during the asexual development of Neurospora crassa  Tamas Zeke , Endre Kokai , Balazs Szoor , Einat Yatzkan , Oded Yarden , a,1 a a,2 b b ´ ´ ´ ¨´´ Krisztina Szirak , Zsigmond Feher , Peter Bagossi , Pal Gergely , Viktor Dombradi * c c d a a, ´ ´ ´ ´ ´ Department of Medical Chemistry, Medical and Health Sciences Center, University of Debrecen, H-4026 Debrecen, Hungary a Department of Plant Pathology and Microbiology, Faculty of Agricultural Food and Environmental Quality Sciences, b Hebrew University of Jerusalem, Rehovot 76100, Israel Department of Human Genetics, Medical and Health Sciences Center, University of Debrecen, H-4012 Debrecen, Hungary c Department of Biochemistry and Molecular Biology, Medical and Health Sciences Center, University of Debrecen, d H-4012 Debrecen, Hungary Received 26 December 2001; received in revised form 4 June 2002; accepted 19 September 2002 Abstract We cloned and sequenced the cDNA and the gene encoding the catalytic subunit of protein phosphatase 1 from the filamentous fungus Neurospora crassa. The gene, designated ppp-1 (phosphoprotein phosphatase 1), was mapped by restriction fragment length polymorphism to linkage group III, in the vicinity of con-7 and trp-1. The expression of the gene was monitored by reverse transcriptase and polymerase chain reactions, by Western blotting, and by protein phosphatase activity assays in synchronized cultures. Transcripts of ppp-1 were detected in the dormant conidia. The abundance of ppp-1 mRNA, Ppp-1 protein, and the activity of protein phosphatase 1 increased during germination and subsequent hyphal elongation as well as during the early stages of aerial mycelium formation.  2002 Elsevier Science Inc. All rights reserved. Keywords: Developmental analysis; Gene cloning; Gene localization; Phosphoprotein phosphatase 1; Protein dephosphorylation; Neurospora crassa 1. Introduction Protein phosphorylation and dephosphorylation reactions are essential elements of signal transduc-  Note: The DNA sequence reported in this publication has been deposited in the EMBL database under the accession number AF124149. *Corresponding author. Tel.: q36-52-412345; fax: q36-52- 412566. E-mail address: dombradi@jaguar.dote.hu (V. Dombradi). ´ Present address: MRC Protein Phosphorylation Unit, 1 School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK. Present address: Department of Zoology, University of 2 Oxford, Oxford OX1 3PS, UK. tion pathways in eukaryotic cells. The dynamic balance between the activities of protein kinases and phosphatases determines the level of phospho- rylation of a given protein. Approximately 1% of the active genes are dedicated to code for the members of the protein kinase superfamily (Plow- man et al., 1999). Protein phosphatases are less numerous and more diverse. Distinct protein tyro- sine phosphatase (PTP), phosphoprotein phospha- tase (PPP), and metal ion dependent protein phosphatase (PPM) enzyme families were identi- fied on the bases of the primary structures of the catalytic subunits ydomains (Wera and Hemmings,