García-Calero E, Garda A L, Marín F, Puelles L
Department of Human Anatomy, Medical School, University of Murcia, Murcia E30071, Spain.
Gene Expr Patterns. 2006 Oct;6(8):879-85. doi: 10.1016/j.modgep.2006.02.008. Epub 2006 Feb 28.
An unknown chicken gene selected from a published substractive hybridization screen (GenBank Accession No. ; [Christiansen, J.H., Coles, E.G., Robinson, V., Pasini, A., Wilkinson, D.G., 2001. Screening from a subtracted embryonic chick hindbrain cDNA library: identification of genes expressed during hindbrain, midbrain and cranial neural crest development. Mech. Dev. 102, 119-133.]) was deemed of interest because of its dynamic pattern of expression across the forebrain and midbrain regions. A 528bp fragment cloned from early chick embryo cDNA and used for in situ hybridization corresponded to part of the 3' untranslated region of the chicken gene Leucine-rich repeat neuronal protein 1 (Lrrn1). The expression of this gene, mapped in the embryonic chick brain between stages HH10 and HH26, apparently preconfigures the zona limitans thalami site before overt formation of this boundary structure. Apart of colateral expression in the forebrain, midbrain and hindbrain basal plate, the most significant expression of Lrrn1 was found early on across the entire alar plate of midbrain and forebrain (HH10). This unitary domain soon divides at HH14 into a rostral part, across alar secondary prosencephalon and prospective alar prosomere 3 (prethalamus; caudal limit at the prospective zona limitans), and a caudal part in alar prosomere 1 (pretectum) and midbrain. The rostral forebrain domain later downregulates gradually most extratelencephalic signal of Lrrn1, but the rostral shell of zona limitans retains expression longer. Expression in the caudal alar domain also changes by downregulation within its pretectal subdomain. Caudally, the midbrain domain ends at the isthmo-mesencephalic junction throughout the studied period. Embryonic Lrrn1 signal also appears in the somites and in the otic vesicle.
从已发表的消减杂交筛选（GenBank登录号：[克里斯蒂安森，J.H.，科尔斯，E.G.，罗宾逊，V.，帕西尼，A.，威尔金森，D.G.，2001年。从消减的鸡胚后脑cDNA文库筛选：鉴定在后脑、中脑和颅神经嵴发育过程中表达的基因。《发育机制》102卷，第119 - 133页。]）中选出的一个未知鸡基因，因其在前脑和中脑区域的动态表达模式而受到关注。从早期鸡胚cDNA克隆并用于原位杂交的一个528bp片段，对应于鸡富含亮氨酸重复神经元蛋白1（Lrrn1）基因3'非翻译区的一部分。该基因的表达在HH10至HH26阶段的鸡胚脑中定位，显然在丘脑界限带这个边界结构明显形成之前就预先设定了其位置。除了在前脑、中脑和后脑基板有旁侧表达外，Lrrn1最显著的表达在早期出现在中脑和前脑的整个翼板（HH10）。这个单一区域在HH14时很快分为一个前部，跨越翼状次脑泡和预期的翼状原节3（前丘脑；在前丘脑界限带的尾侧界限），以及一个位于翼状原节1（顶盖前区）和中脑的后部。前脑前部区域随后逐渐下调Lrrn1的大多数脑外信号，但丘脑界限带的前部外壳保留表达的时间更长。尾侧翼状区域的表达也通过其顶盖前亚区域内的下调而发生变化。在尾侧，中脑区域在整个研究期间在峡部 - 中脑交界处结束。胚胎期的Lrrn1信号也出现在体节和耳泡中。
