Gene Expression Profiles of MYC+ and MYC- mouse Germinal Center B cells

ABSTRACT: Germinal centers (GC) arise within B cell follicles upon antigenic challenge. In the dark zones (DZ) of GCs, B cells proliferate and hypermutate their immunoglobulin genes, and mutants with increased affinity are positively selected in the light zone (LZ) to either differentiate into plasma and memory cells, or re-enter the DZ for further refinement. However, the molecular circuits governing GC positive selection are not known. Here, we show that the GC reaction requires the biphasic regulation of c-MYC expression, involving its transient induction during early GC commitment, its repression by BCL6 in DZ B cells, and its re-induction in a subpopulation of positively selected LZ B cells destined to DZ re-entry. Accordingly, acute disruption of MYC function in vivo leads to GC collapse, indicating an essential role in GC physiology. These results have implications for our understanding of GC selection and the role of MYC deregulation in B cell lymphomas. We used microarrays to determine the global gene expression programs that distinguish MYC+ GC B cells from their MYC- negative counterparts. GFPMYC+ and GFPMYC- GC B cell subpopulations were collected by Fluorescence Activated Cell Sorting (FACS) from B cell enriched fractions of splenic mononuclear cell pools of GFPMYC knock-in mice (12 days after SRBC immunization). 5-20ng of total RNA (RIN>9) for each sample was used as a template for linear cDNA amplification (Ovation RNA amplification Kit, NuGen). cDNA was labeled using the Encore Biotin Labeling Kit (NuGen) and hybridized to Affymetrix Mouse 430.2 gene expression arrays.

ORGANISM(S): Mus musculus

SUBMITTER: David Dominguez-Sola 

PROVIDER: E-GEOD-38304 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress