Translocation of Neurospora crassa transcription factor NUC-1 into the nucleus is induced by phosphorus limitation.
NUC-1, a basic helix-loop-helix zipper protein, activates the expression of several genes involved in phosphorus acquisition in Neurospora crassa. In the present study we investigated whether posttranscriptional mechanisms control the activity of NUC-1. The NUC-1 level was higher (up to fivefold) in wild-type cells grown at low external phosphate concentration and in mutant strains expressing the phosphorus acquisition genes constitutively than in a wild-type strain grown at high external phosphate concentration. Using indirect immunofluorescence we demonstrated that NUC-1 is localized at least predominantly in the cytosol when wild-type N. crassa is grown with an adequate supply of phosphate, whereas NUC-1 is largely concentrated in the nucleus upon limitation of external phosphate. In mutant strains expressing the phosphorus acquisition genes constitutively, NUC-1 localization was also primarily in the nucleus. Thus, subcellular compartmentation of regulatory proteins is an important mechanism in regulating gene expression in filamentous fungi.
Peleg
Y
Y
Department of Biomolecular Chemistry, University of Wisconsin, Madison 53706, USA.
Addison
R
R
Aramayo
R
R
Metzenberg
R L
RL
D001692:Biological Transport; D002451:Cell Compartmentation; D002467:Cell Nucleus / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D005656:Fungal Proteins / Q000302:isolation & purification / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D009492:Neurospora crassa / Q000235:genetics*; D010758:Phosphorus / Q000172:deficiency*; D014157:Transcription Factors / Q000302:isolation & purification / Q000378:metabolism*
D005656:Fungal Proteins; C079787:NUC-1 protein, Neurospora crassa; D014157:Transcription Factors; D010758:Phosphorus