The avian transcription factor c-Rel is expressed in lymphocyte precursor cells and antigen-presenting cells during thymus development.
Transcription factors of the Rel/NF-kappaB family are widely involved in the immune system. In this study, we investigate the in vivo expression of the avian protein c-Rel in the T-cell lineage during thymus development. The majority of thymocytes do not express the c-Rel protein. However, lymphocyte precursor cells that colonize the thymus express the c-Rel protein shortly after their homing in the organ and before they begin to differentiate. c-Rel is also detected in different subsets of antigen-presenting cells such as epithelial cells, dendritic cells, and macrophages. In vitro studies have shown that Rel/NF-kappaB proteins are sequestered in an inactive form in the cytoplasm by interaction with the IkappaBalpha inhibitory protein. By immunocytochemistry, we show that in vivo c-Rel is localized in the cytoplasm of antigen-presenting cells but in both the cytoplasm and nucleus of lymphocyte precursor cells. The cytoplasmic localization of c-Rel in antigen-presenting cells correlates with a high expression of IkappaBalpha, whereas the nuclear localization of c-Rel in lymphocyte precursor cells correlates with a much lower expression of IkappaBalpha. These results suggest that c-Rel might be constitutively activated in lymphocyte precursor cells.
Huguet
C
C
Laboratoire d'Oncologie Moléculaire, URA1160, Institut de Biologie de Lille, France.
Bouali
F
F
Enrietto
P J
PJ
Stehelin
D
D
Vandenbunder
B
B
Abbadie
C
C
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D015153:Blotting, Western; D002451:Cell Compartmentation; D002454:Cell Differentiation; D002455:Cell Division; D002467:Cell Nucleus; D002642:Chick Embryo; D003593:Cytoplasm; D004268:DNA-Binding Proteins / Q000302:isolation & purification; D006412:Hematopoietic Stem Cells / Q000276:immunology*; D020672:I-kappa B Proteins; D007150:Immunohistochemistry; D008214:Lymphocytes / Q000276:immunology*; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000302:isolation & purification; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis*; D020569:Proto-Oncogene Proteins c-rel; D013950:Thymus Gland / Q000196:embryology* / Q000276:immunology; D014018:Tissue Distribution; D014157:Transcription Factors / Q000096:biosynthesis*
D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D016328:NF-kappa B; D011518:Proto-Oncogene Proteins; D020569:Proto-Oncogene Proteins c-rel; D014157:Transcription Factors; D000072000:NF-KappaB Inhibitor alpha