Disclosed are polynucleotide constructs having a strand linked to a moiety carrying one or more auxiliary moieties. Also disclosed are polynucleotide constructs interrupted with a sugar analogue, and polynucleotide constructs with stereochemical{circumflex over ( )}enriched phosphorothioates. The polynucleotide constructs may be provided as hybridized polynucleotide constructs. Also featured are methods of delivery a polynucleotide construct to a cell and methods of reducing the expression of a protein in a cell by contacting the cell with the disclosed polynucleotide construct or hybridized polynucleotide construct.