Constitutive expression cassettes for regulation of plant expression

The present invention relates to expression cassettes comprising transcription regulating sequences with constitutive expression profiles in plants obtainable from Arabidopsis thaliana genes At5g17920, At3g03780, At2g01100, At2g34770, At5g61560, At4g00830, At3g10220, At4g38520, At3g11110, At2g47170, Atlg64090, At5g60690, Atlg76350, At1g76580, Atlg31930, At5g18230, Atlg20970, or At4g35620. The expression cassettes according to the present invention may be employed for expression of a protein, or expression of an antisense RNA, sense or double-stranded RNA. Preferably, expression of the nucleic acid sequence confers to the plant an agronomically valuable trait. Vectors comprising such an expression cassette, and transgenic host cell or non-human organism comprising the expression cassette or the vector are also enclosed. Also enclosed is a method for identifying and/or isolating a sequence with constitutive transcription regulating activity.