Use of a cDNA expression vector for isolation of mouse interleukin 2 cDNA clones: expression of T-cell growth-factor activity after transfection of monkey cells.

Abstract

A cDNA sequence coding for mouse interleukin 2 (IL-2) has been cloned from a cDNA library prepared from mRNA derived from a concanavalin A-activated mouse T-cell clone. The library was constructed by using the pcD vector system, which permits the expression of cDNA inserts in mammalian cells. Screening of the library was performed by transfecting COS-7 monkey cells with pools of cDNA clones in order to express the products encoded by full-length cDNA inserts. By assaying the supernatant fluid, IL-2 cDNA clones that express T-cell growth-factor (TCGF) activity were identified. The DNA sequence codes for a polypeptide of 169 amino acid residues including a putative signal peptide. The mouse IL-2 amino acid sequence deduced from the nucleotide sequence of its cDNA shares extensive homology with the human IL-2 amino acid sequence reported previously. These results demonstrate that identification of full-length cDNA clones for many lymphokines may be achieved entirely on the basis of detection of the functional polypeptides in mammalian cells.

Structural homologies among the hemopoietins.

“…In the case human IL-2 the N-terminal amino acid v alanine (3)(4)(5)(6). Moreover, there was a stri] homology with the N termini of murine and hi Of the four amino acids following the alani identical in murine and human IL-2 and ml forming the pattern Ala-Pro-Thr-Xaa-Ser.…”

SR alpha promoter: an efficient and versatile mammalian cDNA expression system composed of the simian virus 40 early promoter and the R-U5 segment of human T-cell leukemia virus type 1 long terminal repeat.

“…1A) were constructed by inserting a 267-bp fragment containing R and part of the U5 sequence, from the exact 5' end of R (position 354) to the Sau3AI site in the U5 sequence (position 620) (21) (Fig. 1B), with a sense or antisense orientation, respectively, at the HindIII site immediately downstream of the SV40 early promoter of pSV2-CAT (6 (3 ,ug) was transfected into HOS, a human osteosarcoma cell line (10), by the DEAE-dextran method (32), and CAT activity (6) was assayed after a 30-mn incubation with 50 1Lg of protein at 37°C and is expressed relative to that of pSV2-CAT. The shown).…”

Isolation of cDNA for a human granulocyte-macrophage colony-stimulating factor by functional expression in mammalian cells.

“…est (12). We have adopted this approach to screen a pcD cDNA library prepared with mRNA from a concanavalin A (Con A)-activated human T-cell line for cDNA clones that can express CSF activity in COS-7 monkey cells.…”