title: Gene silencing of transgenes inserted in the Aspergillus nidulans alcM and/or alcS loci.
abstract: While carrying out a systematic disruption of the genes of unknown function in the alc gene cluster from the filamentous fungus Aspergillus nidulans, we observed a strong diminution of the transcription of markers inserted in the alcS gene. This was found to be the case for the two markers tested, nadA (from A. nidulans) and pyrG (from A. fumigatus) involved in purine utilization and uracil/uridine biosynthetic pathway, respectively. The same phenomenon was also observed with insertion of the nadA gene in the alcM locus, another gene of the alc cluster. In the case of nadA, the level of expression was directly correlated to the ability of the corresponding strains to grow on adenine as a sole nitrogen source. The insertion of the pyrG marker into alcS complemented perfectly vegetative growth, but did not allow a proper sexual cycle. This suggests that the lowered pyrG expression is not sufficient to provide the intracellular concentration of pyrimidines required for the sexual cycle. Thus, due caution must be exercised when disrupting genes with pyrG, one of the most commonly employed markers, especially if the gene to be disrupted is involved or suspected to be involved in the sexual cycle.
authors.affiliation: Laboratoire de Biologie Moléculaire de la Cellule, Ecole Normale Supérieure de Lyon, CNRS UMR5239/ENS-Lyon/UCBL, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Robellet
authors.forename: Nathalie
authors.initials: N
authors.lastname: Oestreicher
authors.forename: Audrey
authors.initials: A
authors.lastname: Guitton
authors.forename: Christian
authors.initials: C
authors.lastname: Vélot
mesh_terms: D001233:Aspergillus nidulans / Q000235:genetics*; D020868:Gene Silencing; D005800:Genes, Fungal; D056426:Genetic Loci; D005819:Genetic Markers; D008722:Methods; D014157:Transcription Factors; D019076:Transgenes
chemical_list: D005819:Genetic Markers; D014157:Transcription Factors