The distribution of tenascin-X is distinct and often reciprocal to that of tenascin-C.
The distribution of tenascin-X is distinct and often reciprocal to that of tenascin-C.
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DOI：
10.1083/jcb.125.2.483
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发表时间：
1994-04
影响因子：
7.8
通讯作者：
Chiquet-Ehrismann, R
中科院分区：
文献类型：
--
作者：
Matsumoto, K;Saga, Y;Ikemura, T;Sakakura, T;Chiquet-Ehrismann, R
我们分离到了一个编码小鼠腱蛋白- x （TN-X）的cDNA，这是腱蛋白基因家族的一个新成员。n - x基因位于主要组织相容性复合体（MHC） III类区域，就像它的人类对应物一样。在Northern blots上，我们在分析的大多数组织中检测到约13kb的TN-X mRNA，而在各种小鼠细胞系中检测到约11kb和13kb的mRNA，这表明TN-X转录物可能存在选择性剪接。我们培养了针对细菌中表达的小鼠TN-X片段的抗体，并使用这些抗体在心脏细胞提取物和肾癌细胞系的条件培养基中鉴定了TN-X蛋白。TN-X的亚基分子大小约为500 kD，表明该蛋白可能含有多达40个纤维连接蛋白III型重复序列，使其成为已知的最大的腱连接蛋白家族成员。条件培养基中n- x和纯化后的蛋白均可与肝素结合，但未检测到与tenascin-C （TN-C）、纤连蛋白、层粘连蛋白或胶原结合。因此肝素结合活性可能是腱素的共同特征。n - x mRNA及其蛋白主要在心脏和骨骼肌中表达，但mRNA在大多数组织中均有低水平表达。免疫染色显示该蛋白与肌肉组织的细胞外基质和所有分析组织的血管有关。虽然TN- X基因位于MHC III类位点，但除了血管周围的染色外，在分析的淋巴器官中未表达。在皮肤和消化道组织中，经常观察到TN-X和TN-C的反向分布。
We have isolated a cDNA encoding mouse tenascin-X (TN-X), a new member of the family of tenascin genes. The TN-X gene lies in the major histocompatibility complex (MHC) class III region, as it is the case for its human counterpart. On Northern blots we detected a TN-X mRNA of approximately 13 kb in most tissues analyzed, whereas in various mouse cell lines mRNAs of approximately 11 and 13 kb were detected, suggesting the possibility of alternative splicing of TN-X transcripts. We raised antibodies against mouse TN-X fragments expressed in bacteria and used these antibodies to identify the TN-X protein in heart cell extracts and in the conditioned medium of a renal carcinoma cell line. The subunit molecular size of TN-X is approximately 500 kD, suggesting that the protein may contain up to 40 fibronectin type III repeats, making it the largest tenascin family member known yet. TN-X in conditioned medium, as well as the purified protein bind to heparin, but no binding to tenascin-C (TN-C), fibronectin, laminin or collagens could be detected. Thus the heparin-binding activity may be a common feature of the tenascins. The TN-X mRNA as well as the protein are predominantly expressed in heart and skeletal muscle, but the mRNA is found in most tissues at a low level. Immunostaining showed the protein to be associated with the extracellular matrix of the muscle tissues and with blood vessels in all of the tissues analyzed. Although the TN- X gene lies in the MHC class III locus, it is not expressed in the lymphoid organs analyzed, except for the staining around blood vessels. In skin and tissues of the digestive tract often a reciprocal distribution of TN-X and TN-C was observed.