N-terminally truncated FOXP1 protein expression and alternate internal FOXP1 promoter usage in normal and malignant B cells.

ABSTRACT: Strong FOXP1 protein expression is a poor risk factor in diffuse large B-cell lymphoma and has been linked to an activated B-cell-like subtype, which preferentially expresses short FOXP1 (FOXP1S) proteins. However, both short isoform generation and function are incompletely understood. Here we prove by mass spectrometry and N-terminal antibody staining that FOXP1S proteins in activated B-cell-like diffuse large B-cell lymphoma are N-terminally truncated. Furthermore, a rare strongly FOXP1-expressing population of normal germinal center B cells lacking the N-terminus of the regular long protein (FOXP1L) was identified. Exon-targeted silencing and transcript analyses identified three alternate 5' non-coding exons [FOXP1-Ex6b(s), FOXP1-Ex7b and FOXP1-Ex7c], downstream of at least two predicte

SUBMITTER: Brown PJ 

PROVIDER: S-EPMC5004466 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature