Molecular profiling: Gene expression reveals discrete phases oflens induction and development in Xenopus laevis

[摘要] Purpose: Experimental tissue transplant studies reveal that lensdevelopment is directed by a series of early and late inductiveinteractions. These interactions impart a growing lens-forming biaswithin competent presumptive lens ectoderm that leads to specificationand the commitment to lens fate. Relatively few genes are known whichcontrol these events. Identification of additional genes expressedduring lens development may reveal key players in these processes andhelp to characterize these tissue properties.Methods: A large suite of genes has been isolated that areexpresssed during the process of cornea-lens transdifferentiation (lensregeneration) in Xenopus laevis. Many of these genes are alsoexpressed during embryonic lens development. Genes were selected forexpression analysis via in situ hybridization. This group consisted ofclones with possible roles in cell determination and differentiation aswell as novel clones without previous identities. The spatiotemporalexpression of these genes in conjunction with previously described geneswere correlated with key events during embryonic lens formation.Results: Eighteen of the thirty clones analyzed via in situhybridization demonstrated observable expression in the developing lens.These genes were initially expressed in the presumptive lens ectoderm ata variety of timepoints throughout development. Expression is restrictedto discrete time intervals during lens development. However, in mostcases, expression was maintained throughout lens development after beinginitially upregulated.Conclusions: The expression of these genes suggests that a genetichierarchy exists in which an increasing number of genes are upregulatedand their expression is maintained throughout lens development. Suitesof genes appear to be upregulated at specific timepoints duringdevelopment, correlating with stages of lens induction, specification,commitment, lens placode formation, and lens differentiation, whilesuites at additional timepoints suggest that other, previouslyunreported stages exist as well. This analysis provides a geneticframework for characterizing these processes of lens development.

[学科分类] 生物化学/生物物理