Stability and transcriptional activity of PU.1 variants. (A) Immunoblots generated with a polyclonal anti-PU.1 detection antibody display unstable and semistable protein variants. TIs of PU.1 variants from (B) gnomAD version 2.1.1 or (C) biorepository and index patients with agammaglobulinemia are shown. A dashed line indicates a TI of 0.7. Variants below this line (blue) were considered as LOF variants. (D, upper) A diagram of PU.1 functional domains. Structures relevant to DNA binding within the ETS domain are labeled. (D, lower) Average CADD scores for each nucleotide encoding the PU.1 molecule are displayed. GAPDH, glyceraldehyde-3-phosphate dehydrogenase; PEST, proline, glutamic acid, serine, threonine; WT, wild type.