Cloning, sequence analysis, and expression of the large subunit of the human lymphocyte activation antigen 4F2.

Abstract

Among the earliest expressed antigens on the surface of activated human lymphocytes is the surface antigen 4F2. We have used DNA-mediated gene transfer and fluorescence-activated cell sorting to obtain cell lines that contain the gene encoding the large subunit of the human 4F2 antigen in a mouse L-cell background. Human DNAs cloned from these cell lines were subsequently used as hybridization probes to isolate a full-length cDNA clone expressing 4F2. Sequence analysis of the coding region has revealed an amino acid sequence of 529 residues. Hydrophobicity plotting has predicted a probable structure for the protein that includes an external carboxyl terminus, an internal leader sequence, a single hydrophobic transmembrane domain, and two possible membrane-associated domains. The 4F2 cDNA detects a single 1. (4), and one population of "natural killer-like cells" (5). In T cells and B cells, the 4F2 antigen is the earliest described surface antigen to appear after stimulation with antigen or mitogen. The presence of 4F2 antigen on the cell surface 4 hr after stimulation has linked the expression of the molecule to the G0-G1 transition of the cell cycle (2, 3). Although best studied in lymphocytes, 4F2 antigen expression is not restricted to tissues of lymphoid origin. Several groups have reported the expression of the molecule on actively proliferating cells of various origins, including embryonic skin and lung, basal-layer keratinocytes, fibrosarcomas, osteosarcomas, and rhabdomyosarcomas as well as cells transformed by the DNA tumor virus simian virus 40 (6-9). In fibroblasts, the 4F2 antigen is detectable at low levels on the surface of nondividing cells; however, its expression increases dramatically upon transformation by simian virus 40 and the onset of active cell division (7,9).Although the function of the 4F2 molecule is unknown, its pattern of expression and distribution on cells has indicated a possible role in cell division. Incubation of lymphocytes with the 4F2 monoclonal antibody decreases the level of activation (1, 10) and inhibits the growth ofthe tumor cell line HT-1080 in vitro (7). That molecule may be involved in Na'-dependent, non-ATP-dependent calcium uptake by cells, functioning either as the exchange molecule itself or in a regulatory capacity in association with the actual transporter (11).To gain additional insight into the structure and possible function of the molecule, we have isolated and sequenced a full-length-expressing cDNA clone coding for the large subunit of the 4F2 gene. ¶ We present here the entire amino acid sequence. In addition, we have analyzed the expression of the gene in relation to the cell cycle and present evidence for cell-cycle modulation of 4F2 expression at the mRNA level. These data have been presented in preliminary form elsewhere. 1 1 MATERIALS AND METHODS Tissue Culture. MOLT-4, Daudi, and K562 cells were maintained in RPMI medium, supplemented with 20% (vol/vol) heat-inactivated fetal bovine serum (FBS, GIBCO). LTK-cells (12) and their derivati...

Lamprey lymphocyte-like cells express homologs of genes involved in immunologically relevant activities of mammalian lymphocytes

“…The ORF of the lamprey cDNA sequence translates into 524 amino acid residues, as compared with 529 residues of the human protein (29). The lamprey protein is identical with its human counterpart at 32.7% of the positions (Fig.…”

Enhanced tumorigenicity caused by truncation of the extracellular domain of GP125/CD98 heavy chain

“…Analyses of CD98 cDNAs have revealed that CD98hc is a type II transmembrane glycoprotein (Broer et al, 1995;Lumadue et al, 1987;Parmacek et al, 1989;Quackenbush et al, 1987;Teixeira et al, 1987), which is disul®de-linked to a nonglycosylated member of the permease family, CD98lc (Kanai et al, 1998;Mannion et al, 1998;Mastroberardino et al, 1998;Nakamura et al, 1999;Pfei er et al, 1999;Tsurudome et al, 1999).…”

Isolation and structural characterization of the human 4F2 heavy-chain gene, an inducible gene involved in T-lymphocyte activation.

“…Recently, we and others (26,32,36) (29) or first subcloned into pUC13 (38) or bluescript (Stratagene, La Jolla, Calif.) plasmid vectors. DNA sequencing was performed by the dideoxy-chain termination method of Sanger et al (34).…”