A transcription-factor-binding surface of coactivator p300 is required for haematopoiesis

Abstract

The coactivators CBP (Cre-element binding protein (CREB)-binding protein) and its paralogue p300 are thought to supply adaptor molecule and protein acetyltransferase functions to many transcription factors that regulate gene expression. Normal development requires CBP and p300, and mutations in these genes are found in haematopoietic and epithelial tumours. It is unclear, however, which functions of CBP and p300 are essential in vivo. Here we show that the protein-binding KIX domains of CBP and p300 have nonredundant functions in mice. In mice homozygous for point mutations in the KIX domain of p300 designed to disrupt the binding surface for the transcription factors c-Myb and CREB, multilineage defects occur in haematopoiesis, including anaemia, B-cell deficiency, thymic hypoplasia, megakaryocytosis and thrombocytosis. By contrast, age-matched mice homozygous for identical mutations in the KIX domain of CBP are essentially normal. There is a synergistic genetic interaction between mutations in c-Myb and mutations in the KIX domain of p300, which suggests that the binding of c-Myb to this domain of p300 is crucial for the development and function of megakaryocytes. Thus, conserved domains in two highly related coactivators have contrasting roles in haematopoiesis.

Gene expression changes in normal haematopoietic cells

“…Mice with a CBP-KIX mutation displayed no significant alterations in hematopoiesis, while the mice harboring the same KIX mutation in p300 had multilineage abnormalities. 118 This study stands in contrast to the effect seen by a frank single knockout of each gene, in which a more dramatic disruption of hematopoiesis was seen in the CBP knockout. 119 Certainly, experimental technique variation, specificity of the mutants, and/or the mouse strains in each experiment may have a role in the discordant results; alternatively, each protein may have a distinct function in HSC biology that will be elucidated with further investigation.…”

Histone Deacetylase Inhibitors Enhance Memory and Synaptic Plasticity via CREB: CBP-Dependent Transcriptional Activation

“…Genotyping was performed as described previously (Graves et al, 2002). Cbp KIX/KIX knock-in mice were generated as described previously (Kasper et al, 2002;Wood et al, 2006) and were generously provided by Dr. Paul Brindle (St. Jude Children's Research Hospital, Memphis, TN). Briefly, the targeting vector for CBP contained the following point mutations: Tyr650Ala, Ala654Gln, and Tyr658Ala.…”

“…Mice carrying mutations in three highly conserved residues (Tyr650Ala, Ala654Gln, and Tyr658Ala) within the CBP KIX domain (cbp KIX/KIX ) (Kasper et al, 2002) are essentially normal, apart from a modest decrease in thymus size (Kasper et al, 2002). However, mouse embryonic fibroblast derived from cbp KIX/KIX mice are compromised in their ability to support CREBmediated transcription in transient transfection assays (Kasper et al, 2002), and we have shown recently that cbp KIX/KIX mice have deficits in long-term memory for contextual fear conditioning and novel object recognition (Wood et al, 2006). Thus, the in- Hippocampal slices were treated with vehicle or TSA (indicated by black line) for 20 min before tetanization (indicated by an arrow) and throughout the recording period.…”

“…Phosphorylation of CREB at Ser133 induces the association of CREB with CBP via their KID and KIX domains, respectively (Parker et al, 1996). Mice carrying mutations in three highly conserved residues (Tyr650Ala, Ala654Gln, and Tyr658Ala) within the CBP KIX domain (cbp KIX/KIX ) (Kasper et al, 2002) are essentially normal, apart from a modest decrease in thymus size (Kasper et al, 2002). However, mouse embryonic fibroblast derived from cbp KIX/KIX mice are compromised in their ability to support CREBmediated transcription in transient transfection assays (Kasper et al, 2002), and we have shown recently that cbp KIX/KIX mice have deficits in long-term memory for contextual fear conditioning and novel object recognition (Wood et al, 2006).…”

A functional SUMO-interacting motif in the transactivation domain of c-Myb regulates its myeloid transforming ability

“…Moreover, the transcriptional regulatory activity of Myb is crucial for its transforming ability (Gonda et al, 1989;Lane et al, 1990;Hu et al, 1991). Multiple co-factors like p300/CBP, Mi-2a, FLASH and menin/MLL engage in the regulation of the transactivational activity of c-Myb (Dai et al, 1996;Oelgeschlager et al, 1996;Kasper et al, 2002;Saether et al, 2007;Alm-Kristiansen et al, 2008;Jin et al, 2010). Recently, the importance of coactivation by p300 in myeloid transformation was highlighted using a novel murine hematopoietic cell line transformation assay (Pattabiraman et al, 2009).…”