Soulintzi Nikolitsa, Zagris Nikolas
Division of Genetics and Cell and Developmental Biology, Department of Biology, University of Patras, Patras, Greece.
Cells Tissues Organs. 2007;186(4):243-56. doi: 10.1159/000107948. Epub 2007 Sep 4.
Perlecan is a major heparan sulfate proteoglycan that binds growth factors and interacts with various extracellular matrix proteins and cell surface molecules. The expression and spatiotemporal distribution of perlecan was studied by RT-PCR, immunoprecipitation and immunofluorescence in the chick embryo from stages X (morula) to HH17 (29 somites). Combined RT-PCR and immunohistochemistry demonstrated the expression of perlecan as early as stage X and its presence may be fundamental to the first basement membrane assembly on the epiblast ventral surface at stage XIII (blastula). Perlecan fluorescence was intense in the cells ingressing through the primitive streak and was strong lining the epiblast ventral surface lateral to the streak at stage HH3-4 (gastrula). At stage HH5-6 (neurula), perlecan fluorescence was low in the neuroepithelium and stronger in the apical surface of the neural plate. At stage HH10-11 (12 somites), perlecan fluorescence was intense in the neuroepithelium and was then essentially nondetectable in the neuroepithelium, and the intensity had shifted to the basement membranes of encephalic vesicles by stage HH17. Perlecan immunofluorescence was intense in neural crest cells, strong in pharyngeal arches, intense in thymus and lung rudiments, intense in aortic arches and in dorsal aorta, strong in lens and retina and intense in intraretinal space and in optic stalk, strong in the dorsal mesocardium, myocardium and endocardium, strong in dermomyotome, low in sclerotome in somites, intense in mesonephric duct and tubule rudiments, intense in the lining of the gut luminal surface. Inhibition of the function of perlecan by blocking antibodies showed that perlecan is crucial for maintaining basement membrane integrity which mediates the epithelialization, adhesive separation and maintenance of neuroepithelium in brain, somite epithelialization, and tissue architecture during morphogenesis of the heart tube, dorsal aorta and gut. An intriguing possibility is that perlecan, as a signaling molecule that modulates the activity of growth factors and cytokines, participates in the signaling pathways that guide gastrulation movements and neural crest cell migration, proliferation and survival, cardiac cell proliferation and paraxial mesoderm (somitic) cell proliferation and segmentation.
基底膜聚糖是一种主要的硫酸乙酰肝素蛋白聚糖，它能结合生长因子，并与多种细胞外基质蛋白和细胞表面分子相互作用。通过逆转录聚合酶链反应（RT-PCR）、免疫沉淀和免疫荧光技术，研究了基底膜聚糖在鸡胚从X期（桑椹胚）到HH17期（29体节）的表达及时空分布。RT-PCR和免疫组织化学相结合的方法表明，基底膜聚糖早在X期就已表达，其存在可能是XIII期（囊胚）上胚层腹侧表面第一层基底膜组装的基础。在HH3-4期（原肠胚），通过原条迁入的细胞中基底膜聚糖荧光强烈，且在原条外侧的上胚层腹侧表面也有强烈荧光。在HH5-6期（神经胚），神经上皮中的基底膜聚糖荧光较弱，而在神经板的顶端表面荧光较强。在HH10-11期（12体节），神经上皮中的基底膜聚糖荧光强烈，之后在神经上皮中基本检测不到，到HH17期时，荧光强度转移到脑泡的基底膜。基底膜聚糖免疫荧光在神经嵴细胞中强烈，在咽弓中较强，在胸腺和肺原基中强烈，在主动脉弓和背主动脉中强烈，在晶状体和视网膜中强烈，在视网膜内间隙和视柄中强烈，在背侧心内膜、心肌和心内膜中强烈，在皮肌节中强烈，在体节的生骨节中较弱，在中肾管和肾小管原基中强烈，在肠腔表面的内衬中强烈。用阻断抗体抑制基底膜聚糖的功能表明，基底膜聚糖对于维持基底膜完整性至关重要。基底膜完整性介导了脑内神经上皮的上皮化、黏附分离和维持、体节上皮化以及心脏管、背主动脉和肠道形态发生过程中的组织结构。一个有趣的可能性是，基底膜聚糖作为一种调节生长因子和细胞因子活性的信号分子，参与了引导原肠胚形成运动以及神经嵴细胞迁移、增殖和存活、心脏细胞增殖以及轴旁中胚层（体节）细胞增殖和分段的信号通路。
