Expression of TAL-1 proteins in human tissues.
Rearrangement of the tal-1 gene (also known as SCL or TCL-5) occurs in at least 25% of T-cell acute lymphoblastic leukemias (T-ALLs) and results in the aberrant expression of tal-1 mRNA in the neoplastic cells. Also, tal-1 mRNA is constitutively expressed in erythroid precursors and megakaryocytes. This report describes a direct immunocytochemical study of the distribution and localization of TAL-1 protein in normal human tissues and cell lines using four monoclonal antibodies raised against recombinant TAL-1 proteins. One of these reagents recognizes a protein of 41 kD molecular weight in in vitro-translated TAL-1 proteins, two others recognize proteins of 39 and 41 kD molecular weight, and the fourth antibody also recognizes a TAL-1 protein of 22 kD in addition to the 39- and 41-kD proteins. These anti-TAL-1 antibodies label the nuclei of erythroid precursor cells and megakaryocytes in fetal liver and adult bone marrow. The punctate pattern of nuclear labeling suggests that TAL-1 may comprise part of a novel nuclear structure, similar to that recently found for the PML protein. The nuclei of T cell lines known to express mRNA encoding the full-length TAL-1 protein (eg, CCRF-CEM, RPMI 8402, and Jurkat) are also labeled. A study of normal human tissues (including thymus) showed labeling of smooth muscle, some tissue macrophages, and endothelial cells. TAL-1 protein is undetectable in other cell types. These reagents may play an important role in the diagnosis of T-ALL and could also be used in the context of lymphoma diagnosis on routinely fixed material.
University Department of Cellular Science, John Radcliffe Hospital, Oxford, UK.
K
K
Pulford
N
N
Lecointe
K
K
Leroy-Viard
M
M
Jones
D
D
Mathieu-Mahul
D Y
DY
Mason
D000906:Antibodies; D015703:Antigens, CD / Q000032:analysis; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D001853:Bone Marrow / Q000378:metabolism; D002460:Cell Line; D003001:Cloning, Molecular; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli; D005260:Female; D005434:Flow Cytometry; D015870:Gene Expression; D015321:Gene Rearrangement; D006801:Humans; D007150:Immunohistochemistry; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000097:blood / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009000:Monocytes / Q000378:metabolism; D009928:Organ Specificity; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000276:immunology; D015183:Restriction Mapping; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors; D014407:Tumor Cells, Cultured
D000906:Antibodies; D015703:Antigens, CD; D051792:Basic Helix-Loop-Helix Proteins; D017931:DNA Primers; D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors; C067143:TAL1 protein, human