Identification of a Natural Antisense Transcript of aflR, the Transcriptional Regulator in the Aflatoxin Biosynthesis Pathway in Aspergillus flavus.

Carrie Jacobus1 , Gary Payne 2, and Niki Robertson 1,3.

Author address: 

1Department of Genetics. 2Department of Plant Pathology. 3Department of Botany. NCSU Raleigh, North Carolina.


Natural antisense transcripts (NATs) are involved in gene expression in several eukaryotic systems. Cases of transcriptional interference, RNA masking, and double-stranded RNA dependent mechanisms have all been shown to involve NATs. Recently, antisense transcripts have been identified in the filamentous fungus Neurospora crassa that are complementary to frq, a key component of the circadian clock. An antisense transcript was identified in a cDNA library of another filamentous fungus, Aspergillus flavus. This species among others in the genus Aspergillus produces aflatoxin, the most potent naturally occurring carcinogen. The antisense transcript identified in the cDNA library corresponds to aflR, which is the transcriptional regulator of aflatoxin biosynthesis. This NAT, aflRas, overlaps with the 5' end of aflR and extends into its promoter. RT-qPCR analysis was used to compare aflR and aflRas levels with respect to aflatoxin production at different time points. In addition, an over-expression construct utilizing the alcA promoter to drive expression of alfRas was transformed into A. flavus. These over-expression transformants will provide insight as to the function of aflRas. (Presented at poster number 538)

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Full conference title: 

23rd Fungal Genetics Conference
    • Fungal Genetics Conference 23rd (2002)