Hirsch E, Gullberg D, Balzac F, Altruda F, Silengo L, Tarone G
Dipartimento di Genetica, Biologia e Chimica Medica, Università di Torino, Italy.
Dev Dyn. 1994 Oct;201(2):108-20. doi: 10.1002/aja.1002010203.
Alpha v integrin subunit can dimerize with different beta subunits to form receptors for several matrix proteins. The function of these receptors in vivo is still largely unknown. We examined the localization of alpha v integrin during mouse development and showed that its distribution is dynamically regulated in the glia of the central nervous system and in skeletal muscle. Immunoreactivity in the neural tube was firstly localized at embryonic day 10.5 (E10.5) around cell bodies lining the lumen and along tiny fibres extending towards the outer margin. At E12.5 alpha v distribution follows the highly defined pattern of the radial glia: fascicles of immunoreactive fibres form parallel palisades, in particular along the hindbrain and the spinal cord. At E15.5, although with weaker intensity, alpha v was still detectable in radial glia fibres, and it codistributed with glial fibrillary acidic protein positive fascicles. After birth (P8) alpha v immunoreactivity in the brain and spinal cord decreased dramatically, but remained high in the radial glia of the cerebellum. In adult mice alpha v reactivity in the central nervous system disappeared. During myogenesis alpha v appears at E10.5 in myotomal cells and from E12.5 alpha v was evident in myoblasts and in myotubes. In the developing skeletal muscle of E15.5 embryos, immunoreactivity became more concentrated in the apical portion of the myotubes. In adult striated muscle the amount of alpha v subunit dramatically declined and immunostaining was no longer detectable. During development, alpha v was weakly evident in other sites including heart and endothelia of blood vessels, mesonephric tubula, smooth muscle of the digestive tract, and bronchia. Comparative analysis of the localization of alpha v, alpha 3, and alpha 5 integrin subunits indicated that alpha v has a unique and highly regulated distribution pattern. The distribution in the nervous system is consistent with a role of alpha v in neuron-glia interaction during the organization of the neuronal layers in the brain cortex and in the cerebellum. Moreover, alpha v is likely to be involved in the myotendinous junction during embryonic life, suggesting a dual functional role of this integrin in muscle and nervous tissue.
αv整合素亚基可与不同的β亚基二聚化，形成几种基质蛋白的受体。这些受体在体内的功能仍 largely未知。我们研究了αv整合素在小鼠发育过程中的定位，发现其分布在中枢神经系统的神经胶质细胞和骨骼肌中受到动态调节。神经管中的免疫反应性首先在胚胎第10.5天（E10.5）定位在围绕管腔排列的细胞体周围以及沿着向外缘延伸的细纤维上。在E12.5时，αv分布遵循放射状胶质细胞的高度明确模式：免疫反应性纤维束形成平行的栅栏状，特别是沿着后脑和脊髓。在E15.5时，尽管强度较弱，但αv仍可在放射状胶质细胞纤维中检测到，并且它与胶质纤维酸性蛋白阳性纤维束共分布。出生后（P8），脑和脊髓中的αv免疫反应性急剧下降，但在小脑的放射状胶质细胞中仍保持较高水平。在成年小鼠中，中枢神经系统中的αv反应性消失。在肌发生过程中，αv在E10.5出现在肌节细胞中，从E12.5开始在成肌细胞和肌管中明显可见。在E15.5胚胎发育中的骨骼肌中，免疫反应性在肌管的顶端部分变得更加集中。在成年横纹肌中，αv亚基的数量急剧下降，免疫染色不再可检测到。在发育过程中，αv在其他部位如心脏、血管内皮、中肾小管、消化道平滑肌和支气管中微弱可见。对αv、α3和α5整合素亚基定位的比较分析表明，αv具有独特且高度调节的分布模式。其在神经系统中的分布与αv在大脑皮层和小脑中神经元层组织过程中神经元 - 神经胶质细胞相互作用中的作用一致。此外，αv可能在胚胎期参与肌腱连接，表明这种整合素在肌肉和神经组织中具有双重功能作用。
