A 870 bp promoter fragment of the PDC1 gene that includes the carbon source dependent regulatory regions was investigated using 5' and 3' promoter deletions. The results indicate that glucose and ethanol regulation of PDC1 transcription are independently controlled by distinct cis-acting regions. The consensus sequence AAATCGATA may play a role in this regulation, while the sequence (ATCA)AACCT may be important in transcription initiation.