Solid-phase oligonucleotide labeling with DOTA

This unit describes a method to construct oligonucleotide conjugates labeled with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) on a solid support. A nucleosidic phosphoramidite that contains a protected DOTA ligand compatible with normal chain assembly is prepared first. As the chain assembly is completed, the oligonucleotide is deprotected and converted to the corresponding gadolinium(III) chelate, resulting in an oligonucleotide conjugate containing the chelate at the 5'-terminus.