Conjugate for efficient delivery of short interfering RNA (siRNA) into mammalian cells.

The efficient delivery of short interfering RNAs (siRNAs) into cells provides a powerful approach to study cellular functions. SiRNAs were coupled to the membrane permeant peptides (MPPs) penetratin and transportan to improve their uptake by cells. Thiol-containing siRNAs corresponding to luciferase, or green fluorescent protein (GFP) transgenes, were synthesized and conjugated to penetratin or transportan via a disulfide bond that is labile in the reducing environment of the cytoplasm.

Paired-Box genes are frequently expressed in cancer and often required for cancer cell survival.

The paired-box (PAX) genes encode a family of nine well-characterized paired-box transcription factors, with important roles in development and disease. Although PAX genes are primarily expressed in the embryo, constitutive expression promotes tissue hyperplasia. Rare tumor-specific mutations of PAX genes implicate an oncogenic role, and persistent PAX expression characterizes several tumors.

Specific modification of mitochondrial protein thiols in response to oxidative stress: a proteomics approach.

Mitochondria play a central role in redox-linked processes in the cell through mechanisms that are thought to involve modification of specific protein thiols, but this has proved difficult to assess. In particular, specific labeling and quantitation of mitochondrial protein cysteine residues have not been achieved due to the lack of reagents available that can be applied to the intact organelle or cell. To overcome these problems we have used a combination of mitochondrial proteomics and targeted labeling of mitochondrial thiols using a novel compound, (4-iodobutyl)triphenylphosphonium (IBTP).