Lucey Michelle M, Wang Yan, Bustin Michael, Duncan Melinda K
Department of Biological Sciences, University of Delaware, 327 Wolf Hall, Newark, DE 19716, USA.
Protein Section, Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Gene Expr Patterns. 2008 Jul;8(6):433-437. doi: 10.1016/j.gep.2008.04.002. Epub 2008 Apr 22.
The HMGN proteins are a group of non-histone nuclear proteins that associate with the core nucleosome and alter the structure of the chromatin fiber. We investigated the distribution of the three best characterized HMGN family members, HMGN1, HMGN2 and HMGN3 during mouse eye development. HMGN1 protein is evenly distributed in all ocular structures of 10.5 days post-coitum (dpc) mouse embryos however, by 13.5dpc, relatively less HMGN1 is detected in the newly formed lens fiber cells compared to other cell types. In the adult, HMGN1 is detected throughout the retina and lens, although in the cornea, HMGN1 protein is predominately located in the epithelium. HMGN2 is also abundant in all ocular structures of mouse embryos, however, unlike HMGN1, intense immunolabeling is maintained in the lens fiber cells at 13.5dpc. In the adult eye, HMGN2 protein is still found in all lens nuclei while in the cornea, HMGN2 protein is mostly restricted to the epithelium. In contrast, the first detection of HMGN3 in the eye is in the presumptive corneal epithelium and lens fiber cells at 13.5dpc. In the lens, HMGN3 remained lens fiber cell preferred into adulthood. In the cornea, HMGN3 is transiently upregulated in the stroma and endothelium at birth while its expression is restricted to the corneal epithelium in adulthood. In the retina, HMGN3 upregulates around 2 weeks of age and is found at relatively high levels in the inner nuclear and ganglion cell layers of the adult retina. RT-PCR analysis determined that the predominant HMGN3 splice form found in ocular tissues is HMGN3b which lacks the chromatin unfolding domain although HMGN3a mRNA is also detected. These results demonstrate that the HMGN class of chromatin proteins has a dynamic expression pattern in the developing eye.
HMGN蛋白是一类非组蛋白核蛋白，它们与核心核小体结合并改变染色质纤维的结构。我们研究了三个特征最明确的HMGN家族成员HMGN1、HMGN2和HMGN3在小鼠眼睛发育过程中的分布情况。HMGN1蛋白在妊娠10.5天（dpc）的小鼠胚胎的所有眼部结构中均匀分布，然而，到13.5dpc时，与其他细胞类型相比，在新形成的晶状体纤维细胞中检测到的HMGN1相对较少。在成体中，HMGN1在整个视网膜和晶状体中都能检测到，尽管在角膜中，HMGN1蛋白主要位于上皮细胞中。HMGN2在小鼠胚胎的所有眼部结构中也很丰富，然而，与HMGN1不同的是，在13.5dpc时，晶状体纤维细胞中仍保持强烈的免疫标记。在成体眼中，HMGN2蛋白仍存在于所有晶状体核中，而在角膜中，HMGN2蛋白大多局限于上皮细胞。相比之下，在眼睛中首次检测到HMGN3是在13.5dpc时的假定角膜上皮细胞和晶状体纤维细胞中。在晶状体中直到成年HMGN3仍优先存在于晶状体纤维细胞中。在角膜中，HMGN3在出生时基质和内皮细胞中短暂上调，而在成年期其表达局限于角膜上皮细胞。在视网膜中，HMGN3在约2周龄时上调，并在成年视网膜的内核层和神经节细胞层中以相对较高的水平存在。RT-PCR分析确定在眼部组织中发现的主要HMGN3剪接形式是HMGN3b，其缺乏染色质解折叠结构域，尽管也检测到了HMGN3a mRNA。这些结果表明，染色质蛋白的HMGN类别在发育中的眼睛中具有动态表达模式。
