IDENTIFICATION OF PROKARYOTIC DEVELOPMENTAL STAGES BY STATISTICAL-ANALYSES OF 2-DIMENSIONAL GEL PATTERNS

Multivariate statistical comparisons of two-dimensional protein (2-D) gel patterns were used for the first time to define stages of a biolog ical developmental system. The differentiating procaryote, Streptomycc s coelicolor; was radiolabeled in liquid cultures at 16 intervals duri ng development, and radioactive proteins were separated and quantified on 2-D gels. Cluster, principal component, and correlation analyses c lassified these gel patterns into four distinct groups, each reflectin g a pattern of gene expression specific for a stage of development. Th ese studies focused our attention on a phase of arrested growth as a k ey regulatory transition leading to secondary metabolism and a phase o f renewed growth. Proteins whose synthesis was switched on or off duri ng the ''transitional'' phase (some 21 and 18, respectively) were iden tified and will be the focus of future studies designed to identify th eir physiological or regulatory function.