Regulation of septum formation in Aspergillus nidulans by a DNA damage checkpoint pathway

• Published in: Genetics (Austin) Vol. 148; no. 3; pp. 1055 - 1067
• Main Authors: Harris, S.D, Kraus, P.R
• Format: Journal Article
• Language: English
• Published: United States Genetics Soc America 01.03.1998; Genetics Society of America
• Subjects: ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; ADN; ASPERGILLUS NIDULANS; Aspergillus nidulans - genetics; Aspergillus nidulans - physiology; CELL DIFFERENTIATION; CELL DIVISION; Cell Division - physiology; CELL SEPTATION; CELL SEPTUM; CELL STRUCTURE; Chromosomes, Fungal; Cyclin-Dependent Kinases - metabolism; DAMAGE; DANOS; DEGAT; Deoxyribonucleic acid; DIFERENCIACION CELULAR; DIFFERENCIATION CELLULAIRE; DIVISION CELLULAIRE; DIVISION CELULAR; DNA; DNA Damage; DNA MODIFICATION; DNA Repair; DNA, Fungal - metabolism; ENZYMIC ACTIVITY; ESTRUCTURA CELULAR; FENOTIPOS; FOSFORILACION; Fungi; Genetics; HYPHAE; METABOLISM; METABOLISME; METABOLISMO; MICELIO; MUTANT; MUTANTES; MUTANTS; MYCELIUM; PHENOTYPE; PHENOTYPES; PHOSPHORYLATION; PROTEIN KINASE; PROTEINA QUINASA; PROTEINE KINASE; Signal Transduction; STRUCTURE CELLULAIRE; Time Factors; TIROSINA; TYROSINE; Tyrosine - metabolism
• ISSN: 0016-6731; 1943-2631; 1943-2631
• DOI: 10.1093/genetics/148.3.1055

In Aspergillus nidulans, germinating conidia undergo multiple rounds of nuclear division before the formation of the first septum. Previous characterization of temperature-sensitive sepB and sepJ mutations showed that although they block septation, they also cause moderate defects in chromosomal DNA metabolism. Results presented here demonstrate that a variety of other perturbations of chromosomal DNA metabolism also delay septum formation, suggesting that this is a general cellular response to the presence of sublethal DNA damage. Genetic evidence is provided that suggests that high levels of cyclin-dependent kinase (cdk) activity are required for septation in A. nidulans. Consistent with this notion, the inhibition of septum formation triggered by defects in chromosomal DNA metabolism depends upon Tyr-15 phosphorylation of the mitotic cdk p34nimX. Moreover, this response also requires elements of the DNA damage checkpoint pathway. A model is proposed that suggests that the DNA damage checkpoint response represents one of multiple sensory inputs that modulates p34nimX activity to control the timing of septum formation.