Aspergillus nidulans grows on a myriad of substrates; gene expression is highly regulated to adapt to changes in substrates. AcuK and AcuM transcription factors have been discovered to be involved in the regulation of gluconeogenesis. Research into the expression of genes under AcuK/AcuM control could provide answers to regulatory mechanisms in higher eukaryotes such as humans. Findings from studies on A. nidulans can assist in drug (antifungal) development. This book gives insight into carbon metabolism in A. nidulans and AcuK/AcuM regulation of the expression of selected genes that possess the putative CCGN7CCG sequence in their promoter regions. It explores the conservation of CCGN7CCG in maeA, acuF and alxA (which encode NADP-dependent malic enzyme, phosphoenolpyruvate carboxykinase and alternative oxidase) of other Aspergilli and how these genes are regulated under ethanol induced conditions. The book explains how semi-quantitative RT-PCR analysis can be used to evaluate mRNA levels between acuK248 and acuM301 mutants and the wild type. This book will benefit researchers and students in the field of biochemistry and molecular biology of filamentous fungi.