Identification of Genes Associated with Morphology in Aspergillus niger by Using Suppression Subtractive Hybridization
AUTOR(ES)
Dai, Ziyu
FONTE
American Society for Microbiology
RESUMO
The morphology of citric acid production strains of Aspergillus niger is sensitive to a variety of factors, including the concentration of manganese (Mn2+). Upon increasing the Mn2+ concentration in A. niger (ATCC 11414) cultures to 14 ppb or higher, the morphology switches from pelleted to filamentous, accompanied by a rapid decline in citric acid production. The molecular mechanisms through which Mn2+ exerts effects on morphology and citric acid production in A. niger cultures have not been well defined, but our use of suppression subtractive hybridization has identified 22 genes responsive to Mn2+. Fifteen genes were differentially expressed when A. niger was grown in media containing 1,000 ppb of Mn2+ (filamentous form), and seven genes were expressed in 10 ppb of Mn2+ (pelleted form). Of the 15 filament-associated genes, seven are novel and eight share 47 to 100% identity with genes from other organisms. Five of the pellet-associated genes are novel, and the other two genes encode a pepsin-type protease and polyubiquitin. All 10 genes with deduced functions are either involved in amino acid metabolism-protein catabolism or cell regulatory processes. Northern blot analysis showed that the transcripts of all 22 genes were rapidly enhanced or suppressed by Mn2+. Steady-state mRNA levels of six selected filament-associated genes remained high during 5 days of culture in a filamentous state and remained low under pelleted growth conditions. The opposite behavior was observed for four selected pellet-associated genes. The full-length cDNA of the filament-associated clone, Brsa-25, was isolated. Antisense expression of Brsa-25 permitted pelleted growth and increased citrate production at concentrations of Mn2+ that were higher than the parent strain could tolerate. These results suggest the involvement of the newly isolated genes in the regulation of A. niger morphology.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=383145Documentos Relacionados
- Identification of iron responsive genes by screening cDNA libraries from suppression subtractive hybridization with antisense probes from three iron conditions
- Suppression subtractive hybridization coupled with microarray analysis to examine differential expression of genes in virus infected cells
- Differentially expressed genes in a flock of Chinese local-breed chickens infected with a subgroup J avian leukosis virus using suppression subtractive hybridization
- Enhanced Expression of Interferon-Regulated Genes in the Liver of Patients with Chronic Hepatitis C Virus Infection: Detection by Suppression-Subtractive Hybridization
- Positive selection of candidate tumor-suppressor genes by subtractive hybridization.