Immortalization of Virus-Free Human Placental Cells That Express Tissue-Specific Functions

Lei, K. J., Gluzman, Y., Pan, C. J., Chou, J. Y. (May 1992) Immortalization of Virus-Free Human Placental Cells That Express Tissue-Specific Functions. Molecular Endocrinology, 6 (5). pp. 703-712. ISSN 0888-8809

URL: http://www.ncbi.nlm.nih.gov/pubmed/1318503
DOI: 10.1210/mend.6.5.1318503

Abstract

Human pregnancy-specific glycoproteins (PSGs) are a family of closely related placental proteins that, together with the carcinoembryonic antigen members, comprise a subfamily within the immunoglobulin superfamily. To facilitate study of the control of PSG expression, we immortalized human placental cell lines with adenovirus-origin-minus (ori-)-simian virus-40 (SV40) recombinant viruses containing either wild-type or temperature-sensitive (ts) A mutants of SV40. Cells transformed with the SV40 tsA chimera (HP-A1 and HP-A2), but not the SV40 wild-type chimera (HP-W1), were temperature sensitive for transformation. All three cell lines expressed trophoblast-specific genes, including PSG and the alpha- and beta-subunits of hCG. Human CG-alpha expression was greatly stimulated by (Bu)2cAMP in all three cell lines; shifting HP-A1 and HP-A2 cells to the nonpermissive temperature (39.5 C) further increased hCG-alpha expression. At both 33 C (permissive temperature) and 39.5 C, the transformed placental cells expressed PSG mRNAs of 2.2 and 1.7 kilobases; expression was greatly stimulated by sodium butyrate. In the absence of an inducer, the three placental lines synthesized a PSG of 64 kilodaltons (kDa). In the presence of butyrate, they synthesized PSGs of 72, 64, and 54 kDa, similar to the placental PSGs. However, in placenta the predominant species is the 72-kDa product. At 39.5 C, butyrate selectively increased synthesis of the 72-kDa PSG in HP-A1 and HP-A2 cells. To characterize PSG promoter activity, we constructed chloramphenicol acetyltransferase (CAT) fusion genes containing -809 to -44 basepairs up-stream of the translational start site of the PSG6 gene. Using transient expression assays, we demonstrated that the -809/-44 region of the PSG6 gene contained cis-acting sequences that can direct CAT expression in human placental cells. Sodium butyrate, which stimulates PSG expression, greatly increased CAT activity, indicating that butyrate-induced PSG expression is regulated primarily at the level of gene transcription.

Item Type: Paper
Uncontrolled Keywords: PREGNANCY-SPECIFIC BETA-1-GLYCOPROTEIN HUMAN CARCINOEMBRYONIC ANTIGEN HUMAN CHORIONIC-GONADOTROPIN GENE FAMILY SODIUM-BUTYRATE CHROMOSOMAL LOCALIZATION DIFFERENTIAL EXPRESSION GLYCOPROTEIN GENES MULTIGENE FAMILY RETINOIC ACID
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > genes, structure and function > gene expression
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein expression
CSHL Authors:
Communities: CSHL labs > Wigler lab
Depositing User: Matt Covey
Date: May 1992
Date Deposited: 22 Sep 2015 20:11
Last Modified: 22 Sep 2015 20:11
Related URLs:
URI: http://repository.cshl.edu/id/eprint/31834

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