1 TRIM28 is essential for erythroblast differentiation in the mouse

• Genetic loss of the transcriptional co-repressor TRIM28 in adult mice results in deficient adult erythropoiesis in bone marrow, and anemia. • TRIM28 controls the mRNA levels of multiple erythroid transcription factors, heme biosynthetic enzymes and the apoptotic apparatus. For personal use only.on May 9, 2016. by guest www.bloodjournal.orgFrom 3 In previous mass spectrometry and co-immune precipitation studies, we identified TRIM28 (TIF-1β, KAP-1) as a cofactor that specifically co-purified with an NR2C1/NR2C2 (TR2/TR4) orphan nuclear receptor heterodimer that previous studies had implicated as an embryonic/fetal β-type globin gene repressor. TRIM28 has been characterized as a transcriptional co-repressor that can associate with many different transcription factors and can play functional roles in multiple tissues and cell types. Here we tested the contribution of TRIM28 to globin gene regulation and erythropoiesis using a conditional loss of function in vivo model. We discovered that Trim28 genetic loss i