Shipp M A, Richardson N E, Sayre P H, Brown N R, Masteller E L, Clayton L K, Ritz J, Reinherz E L
Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA.
Proc Natl Acad Sci U S A. 1988 Jul;85(13):4819-23. doi: 10.1073/pnas.85.13.4819.
Common acute lymphoblastic leukemia antigen (CALLA) is a 100-kDa cell-surface glycoprotein expressed on most acute lymphoblastic leukemias and certain other immature lymphoid malignancies and on normal lymphoid progenitors. The latter are either uncommitted to B- or T-cell lineage or committed to only the earliest stages of B- or T-lymphocyte maturation. To elucidate to homogeneity, obtained the NH2-terminal sequence from both the intact protein and derived tryptic and V8 protease peptides and isolated CALLA cDNAs from a Nalm-6 cell line lambda gt10 library using redundant oligonucleotide probes. The CALLA cDNA sequence predicts a 750-amino acid integral membrane protein with a single 24-amino acid hydrophobic segment that could function as both a transmembrane region and a signal peptide. The COOH-terminal 700 amino acids, including six potential N-linked glycosylation sites compose the extracellular protein segment, whereas the 25 NH2-terminal amino acids remaining after cleavage of the initiation methionine form the cytoplasmic tail. CALLA+ cells contain CALLA transcripts of 2.7 to 5.7 kilobases with the major 5.7- and 3.7-kilobase mRNAs being preferentially expressed in specific cell types.
常见急性淋巴细胞白血病抗原（CALLA）是一种100 kDa的细胞表面糖蛋白，在大多数急性淋巴细胞白血病、某些其他未成熟淋巴样恶性肿瘤以及正常淋巴样祖细胞上表达。后者要么未定向到B细胞或T细胞谱系，要么仅定向到B淋巴细胞或T淋巴细胞成熟的最早阶段。为了阐明其同质性，从完整蛋白以及衍生的胰蛋白酶和V8蛋白酶肽段中获得了NH2末端序列，并使用冗余寡核苷酸探针从Nalm-6细胞系λgt10文库中分离出CALLA cDNA。CALLA cDNA序列预测出一种750个氨基酸的整合膜蛋白，带有一个24个氨基酸的单一疏水片段，该片段既可以作为跨膜区域又可以作为信号肽。COOH末端的700个氨基酸，包括六个潜在的N-连接糖基化位点，构成细胞外蛋白片段，而起始甲硫氨酸切割后剩余的25个NH2末端氨基酸形成细胞质尾巴。CALLA+细胞含有2.7至5.7千碱基的CALLA转录本，其中主要的5.7千碱基和3.7千碱基mRNA在特定细胞类型中优先表达。
