Spatiotemporal distribution of caudal-type homeobox proteins during development of the hindgut and anorectum in human embryos.
Spatiotemporal distribution of caudal-type homeobox proteins during development of the hindgut and anorectum in human embryos.
复制标题
人类胚胎后肠和肛门直肠发育过程中尾部型同源框蛋白的时空分布
作者：
Tang XB;Zhang T;Wang WL;Yuan ZW;Bai YZ
背景资料。本研究的目的是确定人类尾型同源异型盒蛋白CDX1、CDX2和CDX4在胚胎后肠和肛门直肠发育过程中的时空分布，并探讨CDX基因在后肠和肛门直肠形态发生中的可能作用。方法：研究方法。将胚胎(89枚)连续和矢状切成切片。免疫组织化学染色显示，孕4~9周，CDX1、CDX2、CDX4蛋白在尾侧中线表达。结果。4周龄时，CDX1、CDX2和CDX4在背侧尿直肠隔、泌尿生殖窦和后肠广泛表达。5~7周龄时，CDX1、CDX2和CDX4阳性细胞主要见于尿肠隔和后肠的间质。CDX2和CDX4免疫反应水平低于CDX1。在第8周和第9周，肛门直肠上皮CDX1和CDX4染色阳性，肛门上皮CDX2染色阳性。结论。CDX蛋白在后肠和肛门直肠的发育过程中不断分布，并在泄殖腔/后肠中呈现重叠的分布模式，这表明它们在人类后肠和肛门直肠的形态发生中起重要作用。CDX基因可能参与了直肠与尿肠隔分离后肛门直肠上皮的发育。
Background. The objectives of this study were to determine the spatiotemporal distribution of human caudal-type homeobox proteins CDX1, CDX2 and CDX4 during development of the hindgut and anorectum in the embryo and to explore the possible roles of CDX genes during morphogenesis of the hindgut and anorectum. Methods. Embryos (89) were cut into sections serially and sagittally. From gestation weeks 4–9, CDX1, CDX2 and CDX4 proteins were detected on the caudal midline by immunohistochemical staining. Results. During week 4, extensive immunoreactivity of CDX1, CDX2 and CDX4 was detected in the dorsal urorectal septum, urogenital sinus and hindgut. From weeks 5–7, CDX1-, CDX2- and CDX4- positive cells were detected mainly in the mesenchyme of the urorectal septum and hindgut. The levels of CDX2 and CDX4 immunoreactivity were lower compared to CDX1. During weeks 8 and 9, the anorectal epithelium stained positive for CDX1 and CDX4, and the anal epithelium was positive for CDX2. Conclusions. The CDX proteins are constantly distributed during development of the hindgut and anorectum and exhibit overlapping distribution patterns in the cloaca/hindgut, suggesting they are important in the morphogenesis of the human hindgut and anorectum. CDX genes might be involved in development of the anorectal epithelium after the rectum has separated from the urorectal septum.