The expression of αA- and βB1-crystallin during normal development and regeneration, and proteomic analysis for the regenerating lens in Xenopus laevis

PURPOSE To explore the expression of the lens crystallins (αA- and βB1-crystallin) in Xenopus laevis embryonic lens development and regeneration and to analyze the order of different crystallins generated in the regenerating lens. METHODS Real Time-PCR, Immunofluorescence, and 2D-PAGE were used to analyze the expressions of αA-crystallin and βB1-crystallin, and related factors during embryonic lens development and regeneration in Xenopus laevis. RESULTS αA-crystallin and βB1-crystallin were first detected at stage 29/30 during normal development, and the two crystallins were simultaneously detected in regeneration. During embryonic lens development, the relative expression level of the βB1-crystallin gene was higher than that of the αA-crystallin gene. In the process of the lens regeneration, however, the relative expression level of the βB1-crystallin gene was lower than that of the αA-crystallin gene. Throughout embryonic lens development, the two crystallin transcripts showed the same variation trends, and similar occurrence did in the regeneration process. Crystallins showed different localization and distribution during the ontogeny and regeneration, especially in the lens fiber region. 2D-electrophores revealed the patterns of the sequential synthesis of crystallins, with regard to the different classes and apparent variations of some auxiliary regulatory factors. CONCLUSIONS The ontogeny and localization of the crystallins during embryonic lens development and regeneration indicated a different development program, although they have identical origins, the ectoderm. The expression level of crystallin transcripts displayed a consistent variation tendency, but the presence of appreciable differences was still exposed. In addition to stably producing the crystallins of different classes in accordance with established procedure, these auxiliary factors may perform the function, to some extent, because of significant changes in their expression throughout the process of lens regeneration.