Transcriptional regulation of transferrin receptor expression by cultured lymphoblastoid T cells treated with phorbol diesters

O. Alcantara, C. A. Denham, J. L. Phillips, D. H. Boldt

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

Expression of transferrin receptors (TFR) is required for lymphocyte proliferation. Treatment of lymphoblastic leukemia cell lines with phorbol diester tumor promoters decreases proliferation and induces differentiation. Among changes induced by phorbol diesters is decreased cell surface expression of TFR. To elucidate effects of phorbols on lymphocyte growth and differentiation, we examined TFR expression by measuring 125I-transferrin binding, levels of TFR mRNA by Northern analysis and dot-blot hybridization, and rates of TFR gene transcription by nuclear run-on experiments in CCRF-CEM lymphoblastoid T cells treated with PMA or phorbol dibutyrate. Cell surface expression of TFR was decreased 60 to 85% within 2 min of exposing cells to phorbols and remained decreased for 96 h. Steady state levels of TFR mRNA decreased to < 30% of control after 48 h. After treating cells with actinomycin D, estimated TFR mRNA t( 1/2 ) was 2.7 h and was unaltered in phorbol-treated cells. Levels of TFR mRNA were not affected by treatment of cells with cycloheximide in either control or phorbol-treated cells. Therefore, post transcriptional mRNA processing by protein factors did not account for decreased TFR mRNA in phorbol-treated cells. Compared to baseline levels, rates of TFR gene transcription in PMA-treated cells increased up to two-fold during the initial 6 h of culture, then decreased over the ensuing 12 h to < 10% of baseline values. This pattern was not seen in control cultures. Therefore, regulation of TFR gene transcription is a consequence of treating CEM cells with phorbol diesters. Cell surface expression of TFR in phorbol-treated lymphoblastoid T cells may be mediated in part at the level of gene transcription.

Original languageEnglish (US)
Pages (from-to)1719-1726
Number of pages8
JournalJournal of Immunology
Volume142
Issue number5
StatePublished - 1989

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

Fingerprint Dive into the research topics of 'Transcriptional regulation of transferrin receptor expression by cultured lymphoblastoid T cells treated with phorbol diesters'. Together they form a unique fingerprint.

  • Cite this