Differential post-transcriptional regulation of p21WAF1/ XXXX levels in the developing nervous system following gamma-irradiation.

@entity1380 @entity899 @entity19 @entity5207 @entity2788 @entity204
Radiation-induced @entity204 in the developing brain is @entity899 -dependent. However, genetic studies indicate that the signalling pathways that couple irradiation to @entity899 expression can vary between different developing neural populations [Herzog et al. (1998) Science, 280, 1089-1091]. Here we establish that signalling downstream of @entity899 also exhibits brain region-specific differences that are associated with the relative vulnerability of some cell populations to radiation-induced killing in the @entity19 . Following gamma-irradiation, @entity899 and @entity5207 , but not @entity1380 , protein levels increased in the developing cerebellum. In contrast, neither @entity5207 nor @entity1380 protein levels were elevated in the @entity2788 following irradiation, despite increased @entity899 expression. In the @entity2788 , @entity899 expression was associated with cells destined to die, whereas in the cerebellum, @entity899 was expressed in both radiation-sensitive and radiation-resistant neuroblasts of the external granule cell layer. Although @entity5207 mRNA was expressed in all @entity899 -positive neuroblasts after irradiation, p21WAF1/ @entity5207 protein was only detected in radiation-resistant neuroblasts of the cerebellum. Thus, @entity5207 was subject to post-transcriptional regulation with p21WAF1/ @entity5207 protein only accumulating in cells destined to survive irradiation. Nevertheless, @entity5207 function was not essential for radiation resistance, as postmitotic neuroblasts in the external granule cell layer were spared in p21WAF1/ @entity5207 knockout @entity19 .
