Comprehensive and comparative analysis of transcription start sites suggests diversity in transcriptional regulation of glycolytic genes in Aspergilli

Author:

Taishi Inoue, Takahiro Shintani, Katsuya Gomi

Author address:

Tohoku University, Sendai, Japan

Full conference title:

15th European Conference on Fungal Genetics 2020

Date: 20 June 2020

Abstract:

The Aspergillus fungi have significant impacts on human society. Because they display the versatility in metabolizing carbon sources, diversity in their primary metabolisms has been discussed mainly based on comparative genomics studies. Meanwhile, our previous study showed that the gene encoding enolase, catalyzing a reversible reaction in glycolytic pathway, has two alternative transcription start sites (TSSs) in Aspergillus oryzae, an industrially important fungus. The two TSSs selection is stringently dependent on difference in fermentable and non-fermentable carbon sources such as glucose and acetate, respectively. In contrast, the two TSSs usage is not conserved in Aspergillus nidulans, suggesting the transcriptional diversity in primary metabolic genes in Aspergilli. In this study, we compared transcriptional profiles associated with primary metabolisms between A. oryzae and A. nidulans, by cap analysis of gene expression (CAGE) that allows genome-wide identification of TSSs simultaneously with expression levels . CAGE data were collected from the mycelium grown with glucose or acetate and mapped to 59 orthologous genes of glycolysis/gluconeogenesis, pyruvate catabolism, TCA cycle, and pentose phosphate pathway. Consequently, 59 genes could be divided into 3 groups; group 1 includes 17 genes (17/59, 29%) expressed higher in the presence of glucose in A. oryzae than in A. nidulans, group 2 includes 10 genes (10/59, 17%) expressed higher in the presence of acetate in A. oryzae than in A. nidulans, and the rest of genes included in group 3 show similar pattern of expression levels in both species. Notably, glycolytic genes were enriched in group 1 (12/17, 71%) and differential TSSs usage between the two species were observed in glycolytic genes encoding aldolase, phosphofructokinase, and pyruvate kinase, in addition to enolase. These results can provide us novel insights on diversity in transcriptional regulation for primary metabolisms in Aspergilli.

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ECFG 15