Taguchi M, Kanno H, Kubota R, Miwa S, Shishiba Y, Ozawa Y
Department of Endocrinology and Metabolism, Toranomon Hospital, Tokyo, Japan.
Mol Genet Metab. 2000 May;70(1):75-80. doi: 10.1006/mgme.2000.2986.
Myocilin is known to be associated with the pathogenesis of juvenile-onset primary open angle glaucoma. The tissue distribution of myocilin transcripts has been analyzed in both humans and mice, and a high level of expression in the retina and skeletal muscle has been reported. The functions of myocilin in these tissues are unknown. We isolated rat myocilin cDNA and examined the expression pattern of myocilin, including its expression in endocrine organs, using Northern blot analysis. The rat myocilin cDNA sequence has two in-frame initiation codons, the upstream and downstream ATGs corresponding to the initiation codon of human and murine myocilin, respectively. It is most likely that the first ATG is a translational initiation codon, since 8 of 13 amino acid residues deduced from the rat cDNA sequence between the first and the second ATGs are the same as those in human myocilin. The open reading frame encodes 502 amino acids. Rat myocilin also has both a myosin-like domain and an olfactmedin-like domain, which have been identified in human and murine myocilin. Northern analysis of rat myocilin mRNA revealed substantial expression in the thyroid gland, as well as in the retina and muscle. No transcripts were detected in other endocrine glands, including the adrenal gland, pituitary, and testis. Myocilin may play an important role in thyroid function. Further study of the expression and role of myocilin in the thyroid is required.
已知肌纤蛋白与青少年型原发性开角型青光眼的发病机制有关。已对人和小鼠的肌纤蛋白转录本的组织分布进行了分析，并且报道其在视网膜和骨骼肌中有高水平表达。肌纤蛋白在这些组织中的功能尚不清楚。我们分离了大鼠肌纤蛋白cDNA，并使用Northern印迹分析检查了肌纤蛋白的表达模式，包括其在内分泌器官中的表达。大鼠肌纤蛋白cDNA序列有两个符合读框的起始密码子，上游和下游的ATG分别对应于人和小鼠肌纤蛋白的起始密码子。很可能第一个ATG是翻译起始密码子，因为从大鼠cDNA序列推导的第一和第二个ATG之间的13个氨基酸残基中有8个与人肌纤蛋白中的相同。开放阅读框编码502个氨基酸。大鼠肌纤蛋白也具有在人和小鼠肌纤蛋白中已鉴定出的肌球蛋白样结构域和嗅觉介质样结构域。大鼠肌纤蛋白mRNA的Northern分析显示在甲状腺以及视网膜和肌肉中有大量表达。在包括肾上腺、垂体和睾丸在内的其他内分泌腺中未检测到转录本。肌纤蛋白可能在甲状腺功能中起重要作用。需要进一步研究肌纤蛋白在甲状腺中的表达和作用。
