Acetyltransferases GCN5 and PCAF Are Required for B Lymphocyte Maturation in Mice

Valentyn Oksenych,Dan Su,Jeremy Daniel

doi:10.3390/biom12010061

Abstract

B lymphocyte development has two DNA recombination processes: V(D)J recombination of the immunoglobulin (Igh) gene variable region, and class switching of the Igh constant regions from IgM to IgG, IgA, or IgE. V(D)J recombination is required for the successful maturation of B cells from pro-B to pre-B to immature-B and then to mature B cells in the bone marrow. CSR occurs outside of the bone marrow when mature B cells migrate to peripheral lymphoid organs, such as spleen and lymph nodes. Both V(D)J recombination and CSR depend on an open chromatin state that makes DNA accessible to specific enzymes, recombination activating gene (RAG), and activation-induced cytidine deaminase (AID). Acetyltransferases GCN5 and PCAF possess redundant functions acetylating histone H3 lysine 9 (H3K9). Here, we generated a mouse model that lacked both GCN5 and PCAF in B cells. Double-deficient mice possessed low levels of mature B cells in the bone marrow and peripheral organs, an accumulation of pro-B cells in bone marrow, and reduced CSR levels. We concluded that both GCN5 and PCAF are required for B-cell development in vivo.

Highlights

The development of B lymphocytes starts in the bone marrow where progenitorB cells using recombination-activating genes (RAG) generate DNA double-strand breaks (DSBs) and initiate V(D)J recombination [1]
We developed a complex mouse model when Pcaf gene was germline-inactivated [32] while floxed Gcn5 gene [33] was conditionally inactivated in B-cell lineages by CRE recombinase expressed under Cd19 promoter [34]
Pcaf alone resulted in 62% Pcaf of B cells after red blood cells had been lysed, which be cell death following the normal development of B cells in bone marrow and migration was comparable to WT mice with 65% of B cells in the blood (p = 0.92)

Summary

Introduction

The development of B lymphocytes starts in the bone marrow where progenitor (pro)B cells using recombination-activating genes (RAG) generate DNA double-strand breaks (DSBs) and initiate V(D)J recombination [1]. In maturating B cells, the V(D)J recombination process is genetic recombination of variable (V), diversity (D), and joining (J) gene segments arranging into a newly formed VDJ part of immunoglobulin gene (Ig) [2,3,4,5,6]. V(D)J recombination, B cells develop from pro-B cells expressing specific markers cluster of differentiation 19 (CD19), B220/CD45, and CD43 (CD19+B220+CD43+) to pre-B cells (CD19+B220+CD43−), immature B (CD19+B220+IgM+, low immunoglobulin M, IgM) and mature B (CD19+B220+IgM+, high IgM) cells in bone marrow [2]. Mature B cells initiate another DNA recombination process to change the constant regions of immunoglobulin genes, referred to as class switch recombination (CSR).

Methods

Results

Conclusion