TY - JOUR
T1 - An analysis of alternatively spliced CD45 mRNA transcripts during T cell maturation in humans
AU - Ratech, Howard
AU - Denning, Stephen
AU - Kaufman, Russel E.
N1 - Funding Information:
1Howard Ratech was supported by KO8-CA01501-05. This research was also supported by Grants AI33009-01 and AI28662. 2Current address: Albert Einstein College of Medicine/Monte®ore Medical Center, Department of Pathology, Bronx, NY 10467.
PY - 1997/5/1
Y1 - 1997/5/1
N2 - CD45 is a transmembrane protein tyrosine phosphatase found on nucleated hematopoietic cells. In humans, multiple protein isoforms of CD45 are produced by alternative mRNA splicing of exons 4, 5, and 6 coding for the extracellular portion. We measured all eight possible CD45 mRNA transcripts using RT-PCR in human thymocytes and T cell lines. We report that only six mRNA transcripts are present in T cells. The high mw CD45 mRNA transcripts containing exon 4 correlated with the stage of T cell maturation: abundant high mw transcripts (30.7% of all CD45 mRNA transcripts) were present in immature, CD3-4-8-triple-negative thymocytes which decreased (7.7%) in intermediate, CD4+8+ double-positive (DP) thymocytes and then increased (13.8% or 16.8%) in mature, CD4+8- or CD4-8+single-positive thymocytes. In addition, there was a complex variation in the spliced mRNA transcripts coding for CD45R(O), CD45R(B), CD45R(BC), CD45R(AB), and CD45R(ABC) protein isoforms. High mw CD45 mRNA transcripts accumulated immediately prior to an important physiologic event such as thymocyte expansion. In addition, we identified linkage between RNA splicing of exons 5 and 6, and splicing of exon 5 only and exons 4, 5, and 6 in FACS-purified CD4+ and CD8+ thymocytes. These data support the developmental regulation of alternatively spliced CD45 mRNA transcripts and suggest that specific CD45 isoforms may play an important role at critical stages of T cell development.
AB - CD45 is a transmembrane protein tyrosine phosphatase found on nucleated hematopoietic cells. In humans, multiple protein isoforms of CD45 are produced by alternative mRNA splicing of exons 4, 5, and 6 coding for the extracellular portion. We measured all eight possible CD45 mRNA transcripts using RT-PCR in human thymocytes and T cell lines. We report that only six mRNA transcripts are present in T cells. The high mw CD45 mRNA transcripts containing exon 4 correlated with the stage of T cell maturation: abundant high mw transcripts (30.7% of all CD45 mRNA transcripts) were present in immature, CD3-4-8-triple-negative thymocytes which decreased (7.7%) in intermediate, CD4+8+ double-positive (DP) thymocytes and then increased (13.8% or 16.8%) in mature, CD4+8- or CD4-8+single-positive thymocytes. In addition, there was a complex variation in the spliced mRNA transcripts coding for CD45R(O), CD45R(B), CD45R(BC), CD45R(AB), and CD45R(ABC) protein isoforms. High mw CD45 mRNA transcripts accumulated immediately prior to an important physiologic event such as thymocyte expansion. In addition, we identified linkage between RNA splicing of exons 5 and 6, and splicing of exon 5 only and exons 4, 5, and 6 in FACS-purified CD4+ and CD8+ thymocytes. These data support the developmental regulation of alternatively spliced CD45 mRNA transcripts and suggest that specific CD45 isoforms may play an important role at critical stages of T cell development.
UR - http://www.scopus.com/inward/record.url?scp=0031149756&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0031149756&partnerID=8YFLogxK
U2 - 10.1006/cimm.1997.1111
DO - 10.1006/cimm.1997.1111
M3 - Article
C2 - 9178637
AN - SCOPUS:0031149756
SN - 0008-8749
VL - 177
SP - 109
EP - 118
JO - Cellular Immunology
JF - Cellular Immunology
IS - 2
ER -