Abstract: The invention relates to nucleic acid sequences isolated from sugarcane and to methods of using them. In particular, the inventions relates to nucleotide sequences which are derived from sugarcane polyubiquitin genes and which are capable of directing constitutive expression of a nucleic acid sequence of interest that is operably linked to the sugarcane polyubiquitin nucleotide sequences. The sugarcane polyubiquitin nucleotide sequences are useful in regulating expression of a nucleic acid sequence of interest in monocotyledonous and dicotyledonous plants.