E2F and Myc-Induced Lymphoma Figure 4. Overall expansion of the B-lineage in response to Myc is not altered by E2F2 status, but E2f2-deficient mice have more progenitor B cells. (A) The percentage of B-lineage cells (B220+) within the bone marrow of normal and pretumorous mice with the indicated genotypes. (B) Proportions of bone marrow B lineage cell populations (B220+), from early to more mature stages, across the E2F2 cohort: surface immunoglobulin negative cells, IgM positive IgD negative cells, IgM positive IgD positive cells, and IgM negative IgD positive cells. (C) For clonogenic pre-B cell progenitor assays, an equivalent number of whole bone marrow cells from 8-week old E2f2+/+, E2f2+/2, and E2f22/2 littermates were plated in methylcellulose formulated for pre-B progenitors. After seven days, the number of progenitors (CFU pre-B) per 56104 input cells was determined by counting the B lineage colonies that had arisen. (D) The proportion of immature B lineage cells (B220+ CD43+) in the bone marrow of normal and pretumorous E2F2 cohort mice of the indicated genotypes. doi:10.1371/journal.pgen.1000640.g004 PLoS Genetics | www.plosgenetics.org 7 September 2009 | Volume 5 | Issue 9 | e1000640