The present invention provides improved hairpin and fractured hairpin constructs for use in gene silencing through the RNA interference pathway. An exemplary short hairpin polynucleotide for use in gene silencing can include a polynucleotide having from about 42 nucleotides to about 106 nucleotides configured for being processed by Dicer. The polynucleotide can include a first region having from about 19 to about 35 nucleotides, a loop region coupled to the first region, the loop region having from about 4 to about 30 nucleotides, and a second region having from about 19 to about 35 nucleotides and having at least about 80% complementarity to the first region. Optionally, one of the first region or second region can have an overhang having less than about 6 nucleotides. Also, the short hairpin can be formed of a plurality of polynucleotides that cooperate to form a hairpin structure.