Zebrafish B Cell Development without a Pre-B Cell Stage, Revealed by CD79 Fluorescence Reporter Transgenes

Liu, X., Li, Y.S., Shinton, S.A., Rhodes, J., Tang, L., Feng, H., Jette, C.A., Look, A.T., Hayakawa, K., Hardy, R.R.
Journal of immunology (Baltimore, Md. : 1950)   199(5): 1706-1715 (Journal)
Registered Authors
Feng, Hui, Jette, Cicely A., Liu, Xingjun, Look, A. Thomas, Rhodes, Jennifer
MeSH Terms
  • Animals
  • Animals, Genetically Modified
  • B-Lymphocytes/physiology*
  • CD79 Antigens/genetics
  • CD79 Antigens/metabolism*
  • Cell Differentiation
  • Cloning, Molecular
  • DNA-Binding Proteins/genetics
  • Fish Proteins/genetics
  • Fish Proteins/metabolism*
  • Genes, Reporter/genetics
  • Green Fluorescent Proteins/genetics
  • Immunoglobulin Heavy Chains/genetics
  • Immunoglobulin Heavy Chains/metabolism
  • Immunoglobulin Light Chains/genetics
  • Immunoglobulin Light Chains/metabolism
  • Kidney/physiology*
  • Lymphocyte Activation
  • Precursor Cells, B-Lymphoid/physiology*
  • Transgenes/genetics
  • Zebrafish/immunology*
  • Zebrafish Proteins/genetics
28739882 Full text @ J. Immunol.
CD79a and CD79b proteins associate with Ig receptors as integral signaling components of the B cell Ag receptor complex. To study B cell development in zebrafish, we isolated orthologs of these genes and performed in situ hybridization, finding that their expression colocalized with IgH-μ in the kidney, which is the site of B cell development. CD79 transgenic lines were made by linking the promoter and upstream regulatory segments of CD79a and CD79b to enhanced GFP to identify B cells, as demonstrated by PCR analysis of IgH-μ expression in sorted cells. We crossed these CD79-GFP lines to a recombination activating gene (Rag)2:mCherry transgenic line to identify B cell development stages in kidney marrow. Initiation of CD79:GFP expression in Rag2:mCherry+ cells and the timing of Ig H and L chain expression revealed simultaneous expression of both IgH-μ- and IgL-κ-chains, without progressing through the stage of IgH-μ-chain alone. Rag2:mCherry+ cells without CD79:GFP showed the highest Rag1 and Rag2 mRNAs compared with CD79a and CD79b:GFP+ B cells, which showed strongly reduced Rag mRNAs. Thus, B cell development in zebrafish does not go through a Raghi CD79+IgH-μ+ pre-B cell stage, different from mammals. After the generation of CD79:GFP+ B cells, decreased CD79 expression occurred upon differentiation to Ig secretion, as detected by alteration from membrane to secreted IgH-μ exon usage, similar to in mammals. This confirmed a conserved role for CD79 in B cell development and differentiation, without the requirement of a pre-B cell stage in zebrafish.
Genes / Markers
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Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Engineered Foreign Genes