Structural Characterization and Expression Analysis of the Neurospora Conidiation Gene con-6

• Published in: Developmental biology Vol. 160; no. 1; pp. 254 - 264
• Main Authors: White, Brian T., Yanofsky, Charles
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.11.1993; Elsevier
• Subjects: Amino Acid Sequence; amino acid sequences; Base Sequence; Biological and medical sciences; Biological Factors - metabolism; conidia; DNA; DNA, Fungal; Fundamental and applied biological sciences. Psychology; Fungal Proteins - biosynthesis; Fungal Proteins - genetics; Gene expression; Gene Expression Regulation, Fungal; Genes, Fungal; genetic transformation; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; multigene family; Neurospora - genetics; Neurospora - physiology; Neurospora crassa; nucleotide sequences; Promoter Regions, Genetic; Regulatory Sequences, Nucleic Acid; Sequence Homology, Amino Acid; spore germination; Spores, Fungal - genetics; sporulation; Fungi; Nucleotide sequence; Germination; Ascomycetes; Neurospora crassa; Mutation; Gene expression; Thallophyta; Conidia
• ISSN: 0012-1606; 1095-564X
• DOI: 10.1006/dbio.1993.1303

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-βGal 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.