Isolation of growth suppressors from a cDNA expression library

We describe an experimental procedure for the isolation of growth inhibitor y sequences from a complex cDNA library, This approach first takes advantag e of the SETGAP technique (selectable expression of transient growth arrest phenotype) to enrich for growth inhibitory sequences, followed by a screen ing procedure to identify individual cDNAs that inhibit cell proliferation. Here we provide a detailed description of the experimental protocol and re port the characterization of two cDNA sequences isolated id our initial scr een of a mouse cDNA Library. One of these cDNAs encodes the mouse ubiquitin -conjugation enzyme UbcM2, The other encodes a truncated form of a novel WD 40 repeat protein, named Bop1, which is conserved from yeast to human. Toge ther, these results demonstrate a new approach for the isolation of growth suppressors from cDNA libraries, and identify a previously unknown gene lik ely to be involved in growth control.