title: The J chain gene is transcribed during B and T lymphopoiesis in humans.
abstract: In mice and chickens, J chain appears to be expressed only in activated B cells and plasma cells. In humans, studies based mainly on transformed cells suggest that J chain expression may initiate during earlier stages in B lineage differentiation. In the present study, we isolated a series of hematopoietic subpopulations from human fetal and adult tissues by immunofluorescence cell sorting and examined each subpopulation for J chain expression by reverse transcriptase-PCR. In fetal and adult bone marrow, J chain transcripts were detected at all stages of B lineage differentiation, including the progenitor (CD34+/CD19-) and pro-B (CD34+/CD19+) cell subpopulations. J chain mRNA was also detected during fetal thymocyte development: double negative (CD4-/CD8-) through single positive (CD4+ or CD8+) cell subpopulations. The J chain message was not detected in peripheral CD3+ T cells, CD14+ monocytes, and CD56+ NK cells from either fetal or adult samples. The nucleotide sequence of J chain PCR products from CD34+/CD19- bone marrow progenitors and CD4+/CD8- thymocytes proved identical to the previously reported sequence of functionally spliced J chain mRNA. These results suggest that the J chain gene is transcriptionally active during early stages of both B cell and T cell differentiation, before the expression of their respective Ag receptors.
authors.affiliation: Division of Developmental and Clinical Immunology, Department of Microbiology, University of Alabama at Birmingham, AL 35294, USA.
authors.forename: F E
authors.initials: FE
authors.lastname: Bertrand
authors.forename: L G
authors.initials: LG
authors.lastname: Billips
authors.forename: G L
authors.initials: GL
authors.lastname: Gartland
authors.forename: H
authors.initials: H
authors.lastname: Kubagawa
authors.forename: H W
authors.initials: HW
authors.lastname: Schroeder
mesh_terms: D000328:Adult; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D005333:Fetus / Q000166:cytology / Q000276:immunology; D005803:Genes, Immunoglobulin; D006410:Hematopoiesis / Q000235:genetics* / Q000276:immunology*; D006801:Humans; D007144:Immunoglobulin J-Chains / Q000235:genetics*; D066298:In Vitro Techniques; D051379:Mice; D008875:Middle Aged; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D014158:Transcription, Genetic
chemical_list: D017931:DNA Primers; D007144:Immunoglobulin J-Chains; D012333:RNA, Messenger