Lu W, Phillips C L, Killen P D, Hlaing T, Harrison W R, Elder F F, Miner J H, Overbeek P A, Meisler M H
Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, 48109, USA.
Genomics. 1999 Oct 15;61(2):113-24. doi: 10.1006/geno.1999.5943.
Mice homozygous for the transgenic insertion in line OVE250 exhibit severe progressive glomerulonephritis. Ultrastructural changes in the glomerular basement membrane (GBM) at 2 weeks of age resemble those in Alport syndrome. The transgenic insertion site was mapped by FISH to mouse chromosome 1 close to Pax3. Genetic and molecular analyses identified a deletion of genomic DNA at the transgene insertion site. Exons 1 through 12 of the collagen IV gene Col4a4, exons 1 and 2 of the adjacent Col4a3 gene, and the intergenic promoter region are deleted. Transcripts of Col4a3 and Col4a4 are undetectable in mutant kidney, and both proteins are missing from the GBM. Persistent cellular proliferation in mutant kidneys suggests that interaction with the extracellular matrix may be important for cell maturation. Evolutionarily conserved sequence elements in the promoter regions of human and mouse Col4a3 and Col4a4 include a 19-bp element that was tandemly duplicated in the human lineage and a CTC box element common to several genes encoding extracellular matrix proteins. This new animal model of Alport syndrome, Col4Delta3-4, lacks both alpha3 and alpha4 chains of collagen IV and exhibits an earlier disease onset than mice lacking alpha3 only.
OVE250品系中因转基因插入而纯合的小鼠表现出严重的进行性肾小球肾炎。2周龄时肾小球基底膜（GBM）的超微结构变化类似于Alport综合征中的变化。通过荧光原位杂交（FISH）将转基因插入位点定位到小鼠1号染色体上靠近Pax3的位置。遗传和分子分析确定在转基因插入位点存在基因组DNA缺失。IV型胶原基因Col4a4的第1至12外显子、相邻的Col4a3基因的第1和2外显子以及基因间启动子区域被缺失。在突变体肾脏中检测不到Col4a3和Col4a4的转录本，并且GBM中这两种蛋白质均缺失。突变体肾脏中持续的细胞增殖表明与细胞外基质的相互作用可能对细胞成熟很重要。人和小鼠Col4a3和Col4a4启动子区域中进化保守的序列元件包括在人类谱系中串联重复的一个19bp元件以及几个编码细胞外基质蛋白的基因共有的一个CTC盒元件。这种新的Alport综合征动物模型Col4Delta3 - 4缺乏IV型胶原的α3和α4链，并且比仅缺乏α3的小鼠发病更早。
