Role of QN1 protein in cell proliferation arrest and differentiation during the neuroretina development

In this report, we describe the involvement of the quail neuroretina 1 (QN1 ) protein in retinal development. The Qn1 cDNA was isolated as a gene speci fically expressed at the onset of neuronal cell cycle withdrawal (Bidou et al., Mech. Dev. 43 (1993) 159). Qn1 is located in the cytoplasm in prolifer ating cells during the early stages of the development. Its distribution ch anges, becoming predominantly nuclear, in neurons during establishment of t he quiescent state upon the differentiation. We decreased the amount of QN1 protein by an antisense strategy in vitro or in vivo. This decrease of the amount of QN1 protein results in additional mitosis and in severe abnormal ities such as retinal dysplasia. Our results suggest that QN1 plays a key r ole at the onset of neuronal cell cycle withdrawal. (C) 2001 Elsevier Scien ce Ireland Ltd. All rights reserved.