ZFIN ID: ZDB-PUB-170726-12
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.
Date: 2017
Source: 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
Keywords: none
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
PubMed: 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.