Structural organization of the rat thy-1 gene.
Structural organization of the rat thy-1 gene.
复制标题
大鼠 thy-1 基因的结构组织。
作者：
Seki,T;Moriuchi,T;Chang,HC;Denome,R;Silver,J
Thy-1 is a differentiation marker expressed predominantly on thymocytes, T cells and brain tissue1. Its presence on murine peripheral T cells but not B cells has long been used to distinguish between these two populations of lymphocytes2. Although analogues of Thy-1 have been described in several mammalian species3–6, its tissue distribution in different species varies widely7,8, precluding its use as T-cell-specific marker. The Thy-1 molecule is a cell-surface glycoprotein of relative molecular mass 18,000, one-third of which represents carbohydrate9; the protein moieties of the rat and murine Thy-1 molecules10have been sequenced and found to consist of 111 and 112 amino acids, respectively. An unusual aspect of Thy-1 is the apparent absence of a hydrophobic segment comparable to that observed in other membrane gly-coproteins which would allow integration of Thy-1 within the membrane lipid bilayer. This has prompted speculation that Thy-1 is anchored to the cell surface by some other hydrophobic component such as glycolipid. Here we report the structure ofthy-1complementary DNA and genomic clones and describe the exon-intron organization of the gene. More importantly, our data indicate that Thy-1 is initially synthesized as a molecule of 142 amino acids, 31 amino acids longer at the carboxyl end than the Thy-1 molecule isolated and characterized by Campbellet al11. An extremely hydrophobic region of 20 amino acids lies within this 31-amino acid stretch and may represent the transmembrane segment responsible for anchoring Thy-1 to the cell membrane.
