Targeted disruption of the LAMA3 gene in mice reveals abnormalities in survival and late stage differentiation of epithelial cells.
Targeted disruption of the LAMA3 gene in mice reveals abnormalities in survival and late stage differentiation of epithelial cells.
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小鼠中的LAMA3基因的靶向破坏揭示了上皮细胞的生存和晚期分化的异常。
DOI：
10.1083/jcb.145.6.1309
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发表时间：
1999-06-14
影响因子：
7.8
通讯作者：
Carter, W G
中科院分区：
文献类型：
--
作者：
Ryan, M C;Lee, K;Miyashita, Y;Carter, W G
层粘连蛋白5分别通过整合素α6β4和α3β1调控上皮细胞的锚定和运动。我们利用靶向破坏编码层粘连蛋白5 α3亚基和其他亚型的LAMA3基因，来研究受基底膜粘附（BM）调节的发育功能。在纯合子阴性动物中，发现严重的上皮异常导致新生儿死亡，这与上皮性脑转移中所有α3-层粘连蛋白同工型的去除一致。发现了三种不同细胞功能的改变。首先，利用一种新的组织粘附实验，我们发现突变体BM不能通过整合素α6β4诱导稳定的粘附，这与连接水泡和半粒酶异常的存在一致。在缺乏层粘连蛋白5功能的情况下，我们能够在表皮BM中检测到整合素α3β1的新配体，这表明基底角化细胞可以利用整合素α3β1与替代配体相互作用。其次，我们发现突变上皮细胞的存活缺陷可以通过外源性层粘连蛋白5、胶原或针对整合素α6β4的抗体来修复，这表明通过β1或β4整合素的信号传导足以维持存活。第三，我们在发育中的突变门牙中发现了成釉细胞分化的异常，这表明在突变动物中粘附的下游事件受到了影响。这些结果表明，层粘连蛋白5在调节组织组织、基因表达和上皮细胞存活方面具有重要作用。
Laminin 5 regulates anchorage and motility of epithelial cells through integrins α6β4 and α3β1, respectively. We used targeted disruption of the LAMA3 gene, which encodes the α3 subunit of laminin 5 and other isoforms, to examine developmental functions that are regulated by adhesion to the basement membrane (BM). In homozygous null animals, profound epithelial abnormalities were detected that resulted in neonatal lethality, consistent with removal of all α3-laminin isoforms from epithelial BMs. Alterations in three different cellular functions were identified. First, using a novel tissue adhesion assay, we found that the mutant BM could not induce stable adhesion by integrin α6β4, consistent with the presence of junctional blisters and abnormal hemidesmosomes. In the absence of laminin 5 function, we were able to detect a new ligand for integrin α3β1 in the epidermal BM, suggesting that basal keratinocytes can utilize integrin α3β1 to interact with an alternative ligand. Second, we identified a survival defect in mutant epithelial cells that could be rescued by exogenous laminin 5, collagen, or an antibody against integrin α6β4, suggesting that signaling through β1 or β4 integrins is sufficient for survival. Third, we detected abnormalities in ameloblast differentiation in developing mutant incisors indicating that events downstream of adhesion are affected in mutant animals. These results indicate that laminin 5 has an important role in regulating tissue organization, gene expression, and survival of epithelium.