Iivanainen A, Kortesmaa J, Sahlberg C, Morita T, Bergmann U, Thesleff I, Tryggvason K
Department of Medical Biochemistry and Biophysics, Division of Matrix Biology, Karolinska Institute, S-171 77 Stockholm, Sweden.
J Biol Chem. 1997 Oct 31;272(44):27862-8. doi: 10.1074/jbc.272.44.27862.
The complete primary structure of the mouse laminin alpha4 chain was derived from cDNA clones. The translation product contains a 24-residue signal peptide preceding the mature alpha4 chain of 1,792 residues. Northern analysis on whole mouse embryos revealed that the expression was weak at day 7, but it later increased and peaked at day 15. In adult tissues the strongest expression was observed in lung and cardiac and skeletal muscles. Weak expression was also seen in other adult tissues such as brain, spleen, liver, kidney, and testis. By in situ hybridization of fetal and newborn tissues, expression of the laminin alpha4 chain was mainly localized to mesenchymal cells. Strong expression was seen in the villi and submucosa of the developing intestine, the mesenchymal stroma surrounding the branching lung epithelia, and the external root sheath of vibrissae follicles, as well as in cardiac and skeletal muscle fibers. In the developing kidney, intense but transient expression was associated with the differentiation of epithelial kidney tubules from the nephrogenic mesenchyme. Immunohistologic staining with affinity-purified IgG localized the laminin alpha4 chain primarily to lung septa, heart, and skeletal muscle, capillaries, and perineurium.
小鼠层粘连蛋白α4链的完整一级结构源自cDNA克隆。翻译产物在由1792个残基组成的成熟α4链之前包含一个24个残基的信号肽。对整个小鼠胚胎进行的Northern分析显示，在第7天时表达较弱，但随后增加并在第15天达到峰值。在成年组织中，在肺、心脏和骨骼肌中观察到最强的表达。在其他成年组织如脑、脾、肝、肾和睾丸中也可见弱表达。通过对胎儿和新生儿组织进行原位杂交，层粘连蛋白α4链的表达主要定位于间充质细胞。在发育中的肠道绒毛和黏膜下层、围绕分支肺上皮的间充质基质、触须毛囊的外根鞘以及心肌和骨骼肌纤维中可见强表达。在发育中的肾脏中，强烈但短暂的表达与肾间充质中上皮肾小管的分化有关。用亲和纯化的IgG进行免疫组织化学染色将层粘连蛋白α4链主要定位于肺间隔、心脏、骨骼肌、毛细血管和神经束膜。
