The flotation and adsorption of a new polysaccharide konjac gum (KG) on pyrite and talc in the presence of pre-adsorbed potassium butyl xanthate (PBX) is investigated. The micro-flotation results show that KG is a quality depressant for talc and that conditioning the minerals initially with PBX before KG will increase the recovery difference between pyrite and talc. The results of artificially ...

E2a-Pbx1 is a chimeric transcription factor oncoprotein produced by the t(1;19) translocation in human pre-B cell leukemia. Class I Hox proteins bind DNA cooperatively with both Pbx proteins and oncoprotein E2a-Pbx1, suggesting that leukemogenesis by E2a-Pbx1 and Hox proteins may alter transcription of cellular genes regulated by Pbx-Hox motifs. Likewise, in murine myeloid leukemia, transcripti...

The basic helix-loop-helix (bHLH) transcription factor Myod directly regulates gene expression throughout the program of skeletal muscle differentiation. It is not known how a Myod-driven myogenic program is modulated to achieve muscle fiber-type-specific gene expression. Pbx homeodomain proteins mark promoters of a subset of Myod target genes, including myogenin (Myog); thus, Pbx proteins migh...

The t(1;19) chromosomal translocation of pediatric pre-B cell leukemia produces chimeric oncoprotein E2a-Pbx1, which contains the N-terminal transactivation domain of the basic helix-loop-helix (bHLH) transcription factor, E2a, joined to the majority of the homeodomain protein, Pbx1. There are three Pbx family members, which bind DNA as heterodimers with both broadly expressed Meis/Prep1 homeo-...

The basic helix-loop-helix factor Myod initiates skeletal muscle differentiation by directly and sequentially activating sets of muscle differentiation genes, including those encoding muscle contractile proteins. We hypothesize that Pbx homeodomain proteins direct Myod to a subset of its transcriptional targets, in particular fast-twitch muscle differentiation genes, thereby regulating the comp...

HOX proteins are dependent upon cofactors of the PBX family for specificity of DNA binding. Two regions that have been implicated in HOX/PBX cooperative interactions are the YPWM motif, found N-terminal to the HOX homeodomain, and the GKFQ domain (also known as the Hox cooperativity motif) immediately C-terminal to the PBX homeodomain. Using derivatives of the E2A-PBX oncoprotein, we find that ...

The mammalian Pbx homeodomain proteins provide specificity and increased DNA binding affinity to other homeodomain proteins. A cAMP-responsive sequence (CRS1) from bovine CYP17 has previously been shown to be a binding site for Pbx1. A member of a second mammalian homeodomain family, Meis1, is now also demonstrated to be a CRS1-binding protein upon purification using CRS1 affinity chromatograph...