Identification of Myc-dependent and -independent Notch2 signatures in marginal zone B cells.

Marginal zone (MZ) B cells leverage Notch2 signals to attain rapid differentiation responses and positional cues with in the spenic environment. While it is known that a major player in Notch2 signaling in MZ B cells is the proto-oncogene Myc, it is not clear to what extent MZ B cells use Notch2 signals in Myc-independent manner. In this study we conditinally and inducibly deleted Myc in mature B cells and then used in vivo delivery of anti-Notch2 antibodies to separated Myc-dependent and -independent Notch2 signaling in MZ B cells. Overall design: Myc-floxed mice were mated to hCD20Tam-Cre mice to conditionally and inducibly delete Myc in B cells following tamoxifen treatment. Myc conditional knockout (MycFL/FL.hCD20Tam-Cre mice and Myc+/+.hCD20Tam-Cre control animals were fed tamoxifen in their diet for 4 weeks and then treated with anti-Notch2 blocking antibodies or isotype control antibodies for 24 hours prior to sacrifice. Marginal zone B cells (CD19+, CD93-, CD1d+, CD23-) and follicular B cells (CD19+, CD93-, CD1d-, CD23+) were purified by FACS sorting and RNA-sequencing library generation.