Kudo M, Takayama E, Tadakuma T, Shiokawa K
Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Tokyo, Bunkyo-ku, 113, Japan.
Biochem Biophys Res Commun. 1998 Apr 7;245(1):127-32. doi: 10.1006/bbrc.1998.8347.
Different forms of neural cell adhesion molecule (N-CAM) are generated by alternative splicing of primary transcripts and considered to have distinct biological functions. We cloned cDNAs encoding a new form of N-CAMs from the Xenopus heart cDNA library. Comparison of the sequences with chicken and mouse N-CAMs revealed that these clones code for ssd-form N-CAM. We demonstrate by Northern blot analysis that the ssd form is the major form expressed in the Xenopus adult heart. We obtained two types of ssd-form N-CAM, which are transcripts from N-CAM 1 and N-CAM 2 genes. Both types contain muscle specific domain (MSD) but not pi domain. Northern blot analysis also indicated that this form is not expressed in adult brain, in which ld-form N-CAM is the main N-CAM expressed. It is possible that high levels of specific expression of ssd-form N-CAM are related with the differentiation of cardiac muscles.
神经细胞黏附分子（N-CAM）的不同形式是由初级转录本的可变剪接产生的，并被认为具有不同的生物学功能。我们从非洲爪蟾心脏cDNA文库中克隆了编码一种新型N-CAM的cDNA。将这些序列与鸡和小鼠的N-CAM进行比较，发现这些克隆编码的是ssd形式的N-CAM。我们通过Northern印迹分析证明，ssd形式是非洲爪蟾成体心脏中表达的主要形式。我们获得了两种类型的ssd形式的N-CAM，它们是N-CAM 1和N-CAM 2基因的转录本。这两种类型都包含肌肉特异性结构域（MSD），但不包含π结构域。Northern印迹分析还表明，这种形式在成体脑中不表达，在成体脑中，ld形式的N-CAM是主要表达的N-CAM。ssd形式的N-CAM高水平的特异性表达可能与心肌的分化有关。
