Constitutive promoter

The nucleic acid sequence according to claim 2, wherein the functionally active variant is

• a) a size variant of pCS1 of SEQ ID NO:1, preferably comprising the nucleic acid sequence selected from the group consisting of SEQ ID NOs:2, 3, 4, 5, 6, 7 and 8;
• b) a mutant of the pCS1 of SEQ ID NO:1, or a mutant of the size variant of a), which mutant has at least 60% homology to the sequence SEQ ID NO:1 or to the size variant;
• c) a hybrid comprising
• a sequence selected from the group consisting of pCSI of SEQ ID NO:1, a size variant of a), and a mutant of b);
• and
• at least one further sequence selected from the group consisting of pCSI of SEQ ID NO:1, a size variant of a), a mutant of b), and a heterologous sequence;
• or
• d) a sequence which hybridizes under stringent conditions to any of the size variant, or the mutant nucleic acid sequences of a), or b).

A method to identify a constitutive promoter from eukaryotic cells, comprising the steps of

• a) cultivating eukaryotic cells at a high growth rate;
• b) further cultivating the cells at a low growth rate;
• c) providing samples of the cell culture of step a) and b),
• d) performing transcription analysis in said samples and comparing the transcript levels with the transcript levels of the native pGAP promoter of the cells;
• and
• f) selecting the constitutive promoter that has a higher transcription strength as compared to the native pGAP promoter at high and low growth rates, preferably by determining a transcript level of the identified constitutive promoter which is at least 1.1-fold higher as compared to the native pGAP promoter.