Kwiatkowski D J, Mehl R, Yin H L
Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston 02114.
J Cell Biol. 1988 Feb;106(2):375-84. doi: 10.1083/jcb.106.2.375.
Gelsolin is an actin regulatory protein which is unique among vertebrates in that it is found as both an intrinsic cytoplasmic protein and as a secreted plasma protein. We demonstrate that plasma and cytoplasmic gelsolins are derived by alternative transcriptional initiation sites and message processing from a single gene 70 kb long, containing at least 14 exons. Their message and amino acid sequences are identical except at the 5' end/NH2 termini. The cytoplasmic-specific 5' sequence is derived from two exons that encode untranslated sequence, while the plasma message-specific 5' sequence is derived from a single exon that encodes untranslated sequence, the signal peptide, and the first 21 residues of the plasma protein. The two transcriptional initiation sites are separated by greater than or equal to 32 kb. Biosynthetic and RNase protection studies indicate that a number of cell types make both plasma and cytoplasmic gelsolin in widely varying amounts and ratios.
凝溶胶蛋白是一种肌动蛋白调节蛋白，在脊椎动物中独一无二，它既作为一种内在的细胞质蛋白存在，也作为一种分泌型血浆蛋白存在。我们证明血浆和细胞质凝溶胶蛋白是由一个70 kb长、至少包含14个外显子的单一基因通过可变转录起始位点和信息加工产生的。它们的信息和氨基酸序列除了在5'端/氨基末端外是相同的。细胞质特异性的5'序列来自两个编码非翻译序列的外显子，而血浆信息特异性的5'序列来自一个编码非翻译序列、信号肽和血浆蛋白前21个残基的单一外显子。两个转录起始位点相隔大于或等于32 kb。生物合成和核糖核酸酶保护研究表明，许多细胞类型都会产生血浆和细胞质凝溶胶蛋白，其含量和比例差异很大。
