Objectives: We have earlier reported that targeted over-expression of TGF-b1 in teeth results in a novel tooth phenotype mimicking the two most prevalent human tooth disorders namely, dentinogenesis imperfecta II and dentin dysplasia (Thyagarajan et al., JBC, 276: 11016-11020, 2001). This phenotype was associated with discoloration and attrition of teeth due to defective mineralization. The purpose of this study is to identify novel genes altered by over expression of TGF-b1 in teeth. Methods: Proteomic analysis of dTGF-b1 mouse teeth was carried out using two-dimensional gel electrophoresis and mass spectrum analysis. Results: We have identified the novel expression of members of the crystallin family in the developing teeth. aB and b-crystallins were found to be elevated in dTGF-b1 mouse teeth whereas g-crystallins (gB, gC and gF), markers of cell differentiation, were significantly reduced. Conclusions: Since crystallins are considered as stress proteins, their presence in teeth indicates their potential role in stress of physical friction and temperature fluctuation to which teeth are subjected frequently. Supported by 1Z01DE00698-1 (ABK).