NGN 3 and Klf 4 have important role in fetal mouse brain development

SUMMARY Objective : Embryonal brain development including neurogenesis and gliogenesis requires the concerted actions of numerous genes that are regulated at multiple levels. As known, transcription factors have roles in neural and glial development. But the roles of these factors in brain development in different gestational periods are not clear. Method : The gene expression profiles of NGN 3, Klf 4, c-Myc, Nanog, Oct ¾, GATA 4, Sox 2 genes had been searched in brain tissues of mice fetus at the end of the first and the third trimesters. Results : The results were correlated with the results obtained from brain tissue of adult mouse. At the end of the first trimester, higher gene expression levels were found due to internal control in NGN 3, Klf 4, c-Myc, Nanog, Oct ¾. Similar gene expression levels were observed in GATA 4. Dramatically lower gene expressions were analyzed in Sox 2. In each gene, the highest gene expression levels were found in the first trimester. The expression level of each gene was decreased due to time period during the pregnancy. Interestingly, the gene expression levels of NGN 3 and Klf 4 were extremely high due to control gene level in the first and third trimesters in our series. Conclusion: According to these results, NGN 3 and Klf 4 genes have important roles in fetal mice brain development during the gestation period. Keywords: Brain development, neurogenesis, gliogenesis, gene expression, NGN 3, Klf 4 OZET Amac : Norogenez ve gliogenezden olusan embriyonal beyin gelisimi farkli asamalarda cesitli genlerin katimli ile duzenlenen bir surectir. Noronal ve glial doku gelisiminde bazi transkripsiyonal faktorlerin rolu oldugu bilinmektedir. Ancak bu transkripsiyonal faktorlerin beyin gelisiminde hamileligin farkli donemlerindeki rolleri tam olarak acik degildir. Yontem: Calismamizda fare fetal beyin dokularinda NGN 3, Klf 4, c-Myc, Nanog, Oct ¾, GATA 4, Sox 2 transkripsiyonal faktor genlerinin ekspresyon duzeylerine hamileligin birinci ve ucuncu trimester sonlarina da donemlerde bakilmistir. Bulgular: Elde edilen sonuclar eriskin fare beyninden elde edilen sonuclarla karsilastirilmistir. Birinci trimester sonunda NGN 3, Klf 4, cMyc, Nanog, Oct ¾ genlerinde kontrole gore yuksek gen ekspresyon duzeyleri saptanirken, GATA 4 geninde kontrole gore benzer gen ekspresyon duzeyi bulunmustur. Sox 2 geninde ise cok dusuk gen ekspresyon duzeyi tespit edilmistir. Her gene icin en fazla ekspresyon duzeyi ilk trimesterda bulunmustur. Bu genlere ait ekspresyon duzeyleri hamilelik suresince zamana bagli olarak azalmistir. Ilginc olarak bizim seride NGN 3 ve Klf 4 gen ekspresyon duzeyleri kontrol gen duzeyine gore birinci ve ucuncu trimetserde oldukca yuksektir. Sonuc : NGN 3 ve Klf 4 genlerinin hamilelik suresince fetal fare beyninin gelisimindeki onemli role sahiptir. Anahtar sozcukler: Beyin gelisimi, norogenez, gliogenez, gen ekspresyonu, NGN 3, Klf 4