Adler R, Lindsey J D, Elsner C L
J Cell Biol. 1984 Sep;99(3):1173-8. doi: 10.1083/jcb.99.3.1173.
We report here that cells present in embryonic chick retinal monolayer cultures express differentiated properties characteristic of chick cones developing in vivo. Cell suspensions from 8-d chick embryo retina (a stage when photoreceptor differentiation has not yet started) were cultured for up to 7 d in low density, glial-free monolayers. Under these conditions, monopolar cells represent approximately 40% of the total number of process-bearing neurons. After 6 d in vitro, most of these monopolar cells showed morphological features reminiscent of developing chick cones. These features could be detected with phase-contrast microscopy, lectin cytochemistry, and transmission and scanning electron microscopy. Characteristic cone traits expressed by cultured monopolar cells included the following: (a) a highly polarized organization; (b) a single, short, usually unbranched neurite; (c) the polarized position of the nucleus close to the origin of the neurite; (d) characteristic cone inner segment features such as abundant free ribosomes, a polarized Golgi apparatus, a cluster of mitochondria distal to the nucleus, a big, membrane-bound, pigment-containing vacuole reminiscent of the "lipid droplet" characteristic of chick cones, and at least in some cases, a well-developed paraboloid; (e) the presence of a complex of apical differentiations including abundant microvilli and in some cases also a cilium-like process; and (f) the staining of the apical region of the cell with peanut lectin, which has been shown to be selective for chick embryo cones (Blanks, J.C., and L.V. Johnson, 1983, J. Comp. Neurol., 221:31-41; and Blanks, J.C., and L.V. Johnson, 1984, Invest. Ophthalmol. Visual Sci., 25:546-557). This pattern of differentiation achieved by 8-d chick retina cells after 6 d in vitro is similar to that shown by 14-d-old chick embryo cones in vivo. Outer segments are not present at this stage of development either in vivo or in vitro. This experimental system is now being used to search for cellular and molecular signals controlling survival and differentiation of cone cells.
我们在此报告，鸡胚视网膜单层培养物中的细胞表现出在体内发育的鸡视锥细胞的分化特性。从8日龄鸡胚视网膜（光感受器分化尚未开始的阶段）获得的细胞悬液，在低密度、无胶质的单层培养物中培养长达7天。在这些条件下，单极细胞约占具有突起的神经元总数的40%。体外培养6天后，这些单极细胞中的大多数呈现出类似于正在发育的鸡视锥细胞的形态特征。这些特征可以通过相差显微镜、凝集素细胞化学、透射电子显微镜和扫描电子显微镜检测到。培养的单极细胞所表现出的典型视锥细胞特征如下：（a）高度极化的组织结构；（b）单个、短且通常无分支的神经突；（c）细胞核靠近神经突起始处的极化位置；（d）典型的视锥细胞内段特征，如丰富的游离核糖体、极化的高尔基体、细胞核远端的线粒体簇、一个大的、膜结合的、含色素的液泡，类似于鸡视锥细胞的“脂滴”特征，并且至少在某些情况下，有发育良好的抛物面；（e）存在包括丰富微绒毛以及在某些情况下还有类似纤毛突起的顶端分化复合体；（f）细胞顶端区域用花生凝集素染色，花生凝集素已被证明对鸡胚视锥细胞具有选择性（布兰克斯，J.C.，和L.V.约翰逊，1983年，《比较神经学杂志》，221:31 - 41；以及布兰克斯，J.C.，和L.V.约翰逊，1984年，《Invest. Ophthalmol. Visual Sci.》，25:546 - 557）。8日龄鸡视网膜细胞在体外培养6天后所达到的这种分化模式，类似于14日龄鸡胚视锥细胞在体内所呈现的模式。在体内或体外的这个发育阶段都不存在外段。这个实验系统现在正被用于寻找控制视锥细胞存活和分化的细胞及分子信号。
