Fig. 3: AID deficiency leads to an increased ER stress response in CLL cells and B cells, particularly through the IRE1/XBP1s pathway.

A Gene set enrichment analysis from RNA sequencing of Eμ-TCL1 and AID^−/−/Eμ-TCL1 CLL cells shows that mRNAs related to the unfolded protein response are upregulated in AID^−/−/Eμ-TCL1 CLL cells. B CLL cells purified from the spleens of 4 Eμ-TCL1 and 4 AID^−/−/Eμ-TCL1 mice were stimulated with 20 μg/mL LPS for 3 days and lysates were immunoblotted for the indicated proteins. C CLL cells purified from the spleens of Eμ-TCL1 and AID^−/−/Eμ-TCL1 mice were stimulated with 20 μg/mL LPS for 3 days and lysates were immunoblotted for the indicated proteins. D B cells purified from the spleens of WT and AID^−/− mice were stimulated with 20 μg/mL LPS for 3 days and lysates were immunoblotted for the indicated proteins. E B cells purified from the spleens of WT and AID^−/− mice were stimulated with 20 μg/mL LPS for 3 days, starved in cysteine- and methionine-free medium for 1 h, radiolabeled for 20 min, and chased for the indicated times. Lysates were immunoprecipitated with an anti-XBP1s antibody and analyzed by SDS-PAGE and autoradiography. F–G B cells purified from the spleens of WT and AID^−/− mice were stimulated with 20 μg/mL LPS for 3 days and lysed for purification of RNA. The mRNA levels of XBP1s (F) and XBP1u (G) were measured by quantitative RT-PCR in triplicate. Data were normalized to UBC (a house-keeping gene) and shown as means ± SD. H B cells purified from the spleens of WT and AID^−/− mice were stimulated with 20 μg/mL LPS for 2 days and subsequently treated with 10 μg/mL tunicamycin for indicated times. Lysates were immunoblotted for the indicated proteins. I CLL cells purified from the spleens of Eμ-TCL1 and AID^−/−/Eμ-TCL1 mice were stimulated with 20 μg/mL LPS for 2 days and subsequently treated with 10 μg/mL tunicamycin for indicated times. Lysates were immunoblotted for the indicated proteins.