The present application relates to a novel conjugate group linkable to a compound (such as a therapeutic compound), for use in directing the compound to a target in the body. The conjugate group disclosed herein can enable an expression-inhibitory oligonucleotide (such as a RNAi reagent) to target liver cells to regulate gene expression. The conjugate group disclosed herein has a variety of applications when linked to expression-inhibitory oligonucleotides, comprising applications in therapy, diagnosis, target verification, and genome development. A composition comprising the conjugate group disclosed herein can mediate expression of target nucleic acid sequences in liver cells (such as hepatocytes) when linked to expression-inhibitory oligonucleotides, and can be used for treatment of diseases or disorders responding to the gene expression or activity of cells, tissues, or organisms.