Fuente: WIPO "biotechnology" The present invention is directed to nucleic acid target-specific chimeric proteins comprising a nuclear-envelope and/or nuclear-lamina binding domain and a DNA binding domain. These proteins, as well as the nucleic acids encoding those proteins, can be used in methods to repress or down-regulate expression of selected genes. The DNA binding domains are preferably from naturally-occurring zinc finger proteins (ZFPs) or artificial zinc finger proteins (AZPs). Molecular switch systems for gene regulation are also provided.