C57BL/6-Ly5 Antigen (Ptprc) Congenic Strain
The protein-tyrosine phosphatase, receptor type, C (Ptprc), also known as Ly5 or Cd45 gene of the mouse, encodes a set of transmembrane glycoprotein isoforms expressed only on hematopoietic cells [1, 2]. Ptprc was found to express in multiple forms by alternative splicing of different exons , and in allelic forms designated as Ly5.1/Cd45.1 of SJL/J and Ly5.2/Cd45.2/ of C57BL/6J [4, 5]. A Congenic strain, B6.SJL-Ptprca/Boy has been generated by backcrossing SJL/J carrying Ptprca (Ly5a/Cd45a, Ly5.1/Cd45.1) to the C57BL/6 background strain for hematological studies . RIKEN BRC distributes B6.SJL-Ptprca/BoyYuoRbrc (C57BL/6-Ly5a, C57BL/6-Ly5.1, RBRC00126) mice (Fig. 1) as a useful cell marker system in bone marrow transplantation studies. The specific mouse monoclonal antibodies for the Cd45.1 and Cd45.2 have been exploited  and widely used to distinguish hematopoitetic cells of donor and recipient mice. A typical transplantation experiment is shown in Fig. 2.
Revision of gene and allele names for Ptprc (Ly5/Cd45) have led to much confusion regarding antigen specificity and allelic symbols . Present and past nomenclature of Ly5 gene is summarized in Table 1.
Komura, et al. (1975), described an antigen expressed on T cells, and designated the specificity on C57BL/6 cells as Ly5.1 and on SJL cells as Ly5.2 . According to gene naming convention for alleles, the C57BL/6 allele became Ly5a and SJL/J allele became Ly5b.
In 1987, Morse et al. proposed a revision of nomenclature of mouse lymphocyte antigens, which led to a reversed designation . Consequently, the B6 allele became Ly5b (antigen specificity Ly5.2) and the SJL allele became Ly5a (antigen specificity Ly5.1).
A further revision was made on the cell surface antigens by Morse in 1992, where Ly5 became Cd45.
Finally, the gene name was changed to Ptprc in 1993, based on the work by Charbonneau et al. who demonstrated homology between a tyrosine phosphatase and CD45 protein . This led to the present nomenclature of the B6 as Ptprcb and the SJL as Ptprca.
|Depositor||:||Dr. Toshitada Takahashi, Aichi Cancer Center Research Institute|
|References||:||1.||Komura K, Itakura K, Boyse EA, John M. Ly-5: a new lymphocyte antigen system.Immunogenetics. 1975 1:452-456.|
|2.||Charbonneau H, Tonks NK, Walsh KA, Fischer EH. The leukocyte common antigen (CD45): a putative receptor-linked protein tyrosine phosphatase. Proc Natl Acad Sci U S A.1988 Oct;85(19):7182-6.|
|3.||Saga Y, Tung JS, Shen FW, and Boyse EA. Sequences of Ly-5 cDNA: isoform-related diversity of Ly-5 mRNA. PNAS USA. 1986 83: 6940-6944.|
|4.||Shen FW, Tung JS, and Boyse EA. Further definition of the Ly-5 system.Immunogenetics. 1986 24: 146-149.|
|5.||Tung JS, Scheid MP, Pierotti MA, Hammerling U, and Boyse EA. Structural features and selective expression of three Ly-5+ cell-surface molecules. Immunogenetics. 1981 14: 101-106.|
|6.||Shen FW, Saga Y, Litman G, Freeman G, Tung JS, Cantor H, and Boyse EA. Cloning of Ly-5 cDNA. PNAS USA. 1985 82: 7360-7363.|
|7.||Mobraaten LE. Ly5 gene nomenclature, C57BL/6J and SJL/J – A history of change.JAX Notes. 1994 458, 2.|
|8.||Morse HC III, Shen FW, Hammerling U. Genetic nomenclature for loci controlling mouse lymphocyte antigens. Immunogenetics. 1987 25:71-78.|