Structural characterization and expression analysis of the Neurospora conidiation gene con-6.
The gene con-6 of Neurospora crassa is expressed during the formation of asexual spores (conidia), but it is not expressed in mycelium. con-6 mRNA appears upon induction of conidiation and reaches high levels at the late stages of conidiation, and in mature conidia. The CON6 polypeptide and a CON6-beta-Gal fusion protein were present at high levels only in free conidia. Shortly after spore germination con-6 mRNA disappears and the CON6 polypeptide is degraded. CON6 is a small, hydrophilic polypeptide containing a repeat sequence; it not homologous to any known protein but has features resembling the late embryogenesis abundant proteins of maize. Inactivation of con-6 by the repeat-induced point mutation process had no demonstrable effect on formation or germination of conidia. Upstream sequence comparisons for con-6 and other con genes identified a common potential regulatory sequence, designated CRS-B. DNA mobility shift analyses with cell extracts identified a factor that bound to synthetic DNA fragments containing this sequence. This binding factor was present in mycelium but not in conidiating cultures. Experiments with independent integrated con-6'-'lacZ translational fusions revealed substantial variability of expression among transformants carrying identical fusion constructs: This variability may be due to the differential methylation of transformant DNA noted by others.
White
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Department of Biological Sciences, Stanford University, California 94305.
Yanofsky
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D000595:Amino Acid Sequence; D001483:Base Sequence; D001685:Biological Factors / Q000378:metabolism; D004271:DNA, Fungal; D005656:Fungal Proteins / Q000096:biosynthesis / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D009491:Neurospora / Q000235:genetics* / Q000502:physiology; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D017386:Sequence Homology, Amino Acid; D013172:Spores, Fungal / Q000235:genetics
D001685:Biological Factors; C084247:CON-6 protein, Neurospora crassa; D004271:DNA, Fungal; D005656:Fungal Proteins