Assembling a Protein Jigsaw Puzzle

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Science  25 Feb 2000:
Vol. 287, Issue 5457, pp. 1365
DOI: 10.1126/science.287.5457.1365e

Scientists have reasoned that, like pieces of a jigsaw puzzle, if two proteins fit together, then this interaction is likely to contribute to in vivo function. Uetz et al. compare microarray and library variations of the yeast two-hybrid system as a step toward identifying the complete set of interactions that occur among the ∼6000 yeast proteins. In the first approach, 6000 yeast colonies, each containing the activation domain of Gal4 fused to a different open reading frame (ORF), were mated to a separate set of hybrids containing the Gal4 DNA-binding domain fused to one of 192 ORFs. In the second approach, the 6000 ORF-containing varieties were pooled into a library, mated against DNA-binding domain—containing counterparts, and then analyzed in a semi-automated screen.

The microarray approach, although requiring significantly more work and time, provided more positive results per protein than the library approach. Furthermore, the pooling that occurs in the library approach may select against cells that are growing more slowly or mate less efficiently. A total of 957 possible interactions were identified by these approaches, many of which may help to classify proteins of known function but of unknown pathway.—BJ

Nature403, 623 (2000).

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