Expression of the estrogen-regulated gene Nip2 during rat brain maturation

The present study sterns from previous observations demonstrating that in t he neuroblastoma cell line SK-ER3 the mRNA content of the pro-apoptotic gen e Nip2 is decreased following treatment with estradiol. We investigate the content of Nip2 mRNA during the maturation of rat embryo brain and we show that Nip2 mRNA is very low at embryo day 15 and steadily increases up to da y 20. At day 21 Nip2 mRNA is decreased almost to the low levels observed in the mature brain. Studies in neurons from rat embryo at day 18 show that N ip2 mRNA content is significantly decreased by exposure to estradiol at I n M concentration demonstrating that the observations previously done in the SK-ER3 neuroblastoma cell line can be reproduced in neurons in culture. The finding that estrogens may modulate the activity of Nip2 gene activity may be of relevance not only with regard to the effects of estradiol on brain maturation, but also for the understanding of the neuroprotective effects r ecently described for this hormone. (C) 2000 ISDN. Published by Elsevier Sc ience Ltd. All rights reserved.