The Expression Of αA-,βB1-crystallin During Embryonic Lens Development And Regeneration In Xenopus Laevis

Xenopus laevis is probably the most well studied anuran amphibian in laboratories. In the developmental biology field, it is often used as the model species, which is important for the study of the development and function of the related gene, protein in vertebrates. Xenopus laevis can regenerate new lens after origin lens removal, so molecular mechanisms involved in regeneration become the current focus of research. The expression of aA-,βB1-crystallin and crystallin genes was compared by Real-time PCR and immunofluorescence in embryonic lens development and lens regeneration.2D-PAGE was used for proteomic analysis for the regenerating lens.1. Quantitative analysis indicated that the expression of aA-, (3B1-crystallin transcripts showed the same variation trends. During embryonic lens development, their expression displayed the pattern from the low to high and the high to low. With the further development, the expression of the crystallin genes was relatively stable, but the relative expression level of theβB1-crystallin gene was higher than that of the aA-crystallin gene throughout the lens development. In the process of lens regeneration, variation trends of crystallin genes expression was the same as the normal. However, the relative expression level of the aA-crystallin gene was higher than that of theβB1-crystallin gene during the lens regeneration. The results showed the similarities and differencest, and disclosed that some regulation genes played different roles during the two process of lens development. At the same time, some new genes were involved in the process of lens regeneration.2. Immunofluorescence showed that the signals for aA-crystallin andβB1-crystallin were firstly detected at the stage of lens placode. After lens fiber cells were fully differentiated, more βB1-crystallin was expressed thanαA-crystallin in the primary lens fiber, however, almost equal distribution of the two crystallins in the secondary lens fibers. During the lens regeneration, the expression of aA-crystallin andβB1-crystallin was simultaneously detected on day 3. Finally, same distribution ofαA-crystallin andβB1-crystallin was shown in the primary and secondary lens fiber. These implicated that the expression of crystallins may be involved in different procedures because of different signaling pathway and regulation genes.3. Proteomic analyzed that different proteins were synthesized at different regeneration stages.αA-,βB1-, andβA2-crystallin were first synthesized at early regeneration(on day 5 after lens removal). Subsequently, other proteins were synthesized in order with the further regeneration. Lens regeneration showed a pattern of sequential expression of crystallins. By MS, some non-lens proteins showed the change in expression during the lens regeneration, including G protein, retinaldehyde binding protein, centromere protein E. Because of expression variatiom, they may play an important role in the lens regeneration. This implied that the interation between the crystallins also regulated their expression quanlity.The study indicated embryonic lens development and lens regeneration were different processes in Xenopus laevis. Expression pattern of the crystallins and their genes in normal lens development was different that during lens regeneration, suggesting the two processes may involved with different signaling pathway. The study provided some academic evidence for researching lens regeneration.