Systematic identification of cis-silenced genes by trans complementation.

A gene's transcriptional output is the combined product of two inputs: diffusible factors in the cellular milieu acting in trans, and chromatin state acting in cis. Here, we describe a strategy for dissecting the relative contribution of cis versus trans mechanisms to gene regulation. Referred to as trans complementation, it entails fusing two disparate cell types and searching for genes differentially expressed between the two genomes of fused cells.

Identification of functionally important cysteines in the alpha-subunit of transducin by chemical cross-linking techniques.

Transducin (T), the G-protein in the visual system, is a heterotrimer arranged as two functional units, Talpha and Tbetagamma. N,N'-1,2-phenylenedimaleimide (o-PDM) and N,N'-1,4-phenylenedimaleimide (p-PDM), two cysteine specific-homobifunctional agents, were used to covalently cross-link T and its units. A complete inhibition in T function was observed in the presence of these compounds.