Expression of the HOX-2.3 homeobox gene in human lymphocytes and lymphoid tissues.
Homeobox proteins are sequence-specific DNA-binding proteins initially implicated in the control of gene expression in developing tissues; however, there is increasing evidence that these proteins are important in gene regulation in adult tissues. A cDNA for the homeobox gene HOX-2.3 was isolated from an adult human B-lymphocyte cDNA library. Northern blot analysis showed expression of a 1.1 and a 1.6 kb messenger RNA (mRNA) in a human B-cell line. RNase protection assays demonstrated variable expression in both human B- and T-cell lines. Virally transformed and nontransformed lymphocyte cell lines expressed HOX-2.3 transcripts. Essentially no transcripts were found in unactivated normal B and T lymphocytes; however, B-cell activation with Staphylococcus aureus Cowan strain I and phorbol myristate acetate (PMA) or T-cell activation with phytohemagglutinin and PMA were accompanied by a rapid induction of HOX-2.3 expression even in the presence of the protein synthesis inhibitor, cycloheximide. In situ hybridization was performed to examine HOX-2.3 expression in lymphoid tissues. HOX-2.3 mRNA was detected in the thymic cortex from an 8-year-old child, in the germinal centers in adult tonsil, and in a limited number of hematopoietic cells from the bone marrow. These findings suggest the involvement of HOX-2.3 in regulating gene transcription not only in developing tissues but in hematopoietic and lymphoid tissues as well.
Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institute of Health, Bethesda, MD 20892.
Y
Y
Deguchi
J F
JF
Moroney
J H
JH
Kehrl
D000328:Adult; D016375:Antisense Elements (Genetics); D001402:B-Lymphocytes / Q000502:physiology*; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D016208:Databases, Factual; D015870:Gene Expression; D005801:Genes, Homeobox; D006412:Hematopoietic Stem Cells / Q000502:physiology; D006801:Humans; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D015345:Oligonucleotide Probes; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D013601:T-Lymphocytes / Q000502:physiology*
D016375:Antisense Elements (Genetics); D015345:Oligonucleotide Probes; D012333:RNA, Messenger