1(College of Life Science, Langfang Normal University, Langfang 065000, China); 2(Technical Innovation Center for Utilization of Edible and Medicinal Fungi in Hebei Province, Langfang Normal University, Langfang 065000, China)
Abstract: To preliminary explore the biological functions of Aspergillus flavus McrA, the transcription factor gene AfMcrA was cloned by reverse transcription-polymerase chain reaction(RT-PCR). The physicochemical properties, conserved domain, secondary structure, and subcellular localization of AfMcrA were predicted by online tools. The relative expression of the transcript levels of AfMcrA in different cultural periods was detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The results showed that the genomic DNA of AfMcrA was 1 448 bp, containing 4 extrons and 3 introns. The nucleotide sequence of the cDNA of AfMcrA contained an open reading frame of 1 101 bp, encoding a protein of 366 amino acids. Bioinformatics analysis predicted that AfMcrA was an unstable hydrophilic protein with a relative molecular mass of 39.82 kDa. The theoretical isoelectric point of AfMcrA was 8.79,without transmembrane domain nor signal peptide. AfMcrA had a conserved Zn(II)2Cys6 zinc finger domain, termed as a C6 transcription factor. PredictNLS analysis predicted that AfMcrA was located in the nucleus. The secondary structure of AfMcrA primarily consisted of random coils, and the proportion reached 84.43%. qRT-qPCR results revealed that the relative expression level of AfMcrA reached its peak at 6 days after inoculation, which was 15.79 and 14.76 times of that at 2 and 8 days, respectively. Combined with our results and related reports on McrA, it was speculated that AfMcrA may be involved in the regulation of secondary metabolites of A. flavus.
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