The zinc finger protein Gfi-1 can enhance STAT3 signaling by interacting with the STAT3 inhibitor PIAS3.

STAT factors act as signal transducers of cytokine receptors and transcriptionally activate specific target genes. The recently discovered protein PIAS3 binds directly to STAT3 and blocks transcriptional activation. Here, we present experimental evidence implementing the zinc finger protein Gfi-1 as a new regulatory factor in STAT3-mediated signal transduction. The interaction between the two proteins first became evident in a yeast two-hybrid screen but was also seen in coprecipitation experiments from eukaryotic cells. Moreover, we found that both Gfi-1 and PIAS3 colocalize in a characteristic nuclear dot structure. While PIAS3 exerts a profound inhibitory effect on STAT3-mediated transcription of target promoters, Gfi-1 can overcome the PIAS3 block and significantly enhances STAT3-mediated transcriptional activation. In primary T cells, Gfi-1 was able to amplify IL-6-dependent T-cell activation. As Gfi-1 is a known, dominant proto-oncogene, our findings bear particular importance for the recently described ability of STAT3 to transform cells malignantly and offer an explanation of the oncogenic potential of Gfi-1 in T lymphocytes.

Evidence implicating Gfi-1 and Pim-1 in pre-T-cell differentiation steps associated with beta-selection.

After rearrangement of the T-cell receptor (TCR) beta-locus, early CD4(-)/CD8(-) double negative (DN) thymic T-cells undergo a process termed 'beta-selection' that allows the preferential expansion of cells with a functional TCR beta-chain. This process leads to the formation of a rapidly cycling subset of DN cells that subsequently develop into CD4(+)/CD8(+) double positive (DP) cells. Using transgenic mice that constitutively express the zinc finger protein Gfi-1 and the serine/threonine kinase Pim-1, we found that the levels of both proteins are important for the correct development of DP cells from DN precursors at the stage where 'beta-selection' occurs. Analysis of the CD25(+)/CD44(-,lo) DN subpopulation from these animals revealed that Gfi-1 inhibits and Pim-1 promotes the development of larger beta-selected cycling cells ('L subset') from smaller resting cells ('E subset') within this subpopulation. We conclude from our data that both proteins, Pim-1 and Gfi-1, participate in the regulation of beta-selection-associated pre-T-cell differentiation in opposite directions and that the ratio of both proteins is important for pre-T-cells to pass the 'E' to 'L' transition correctly during beta-selection.

The ability of POU family transcription factors to activate or repress gene expression is dependent on the spacing and context of their specific response elements.

The different forms of the Oct-2 and Brn-3 POU family transcription factors can have distinct effects on their target promoters involving both the activation and repression of gene expression. To investigate the requirements for these effects we have altered both the context and spacing of the two TAATGARAT binding sites for these factors within the herpes simplex virus immediate-early 3 gene promoter. We show that the activation of this promoter by Brn-3a and its repression by Brn-3b is dependent on the correct spacing of these binding sites. In contrast, repression of the promoter by Oct-2.4 and Oct-2.5 is dependent on both the spacing and context of these sites with the requirements for repression by Oct-2.4 or Oct-2.5 being different. These effects are discussed in the context of the mechanisms by which POU factors activate or repress their target genes.

Short isoform of POU factor Brn-3b can form a heterodimer with Brn-3a that is inactive for octamer motif binding.

The POU proteins Brn-3a and Brn-3b belong to a family of DNA binding transcription factors that share stretches of extensive homology. Both Brn-3a and Brn-3b are expressed as shorter and longer isoforms. The long form of Brn-3a is able to oncogenically transform primary fibroblasts. By contrast, the short form of Brn-3b (Brn-3b(s)) cannot transform fibroblasts but is able to specifically inhibit the transforming activity of Brn-3a(1). Moreover, Brn-3a(1) can act as a transcriptional transactivator, while Brn-3b(s) is not only unable to do so but in addition specifically inhibits the tranactivating activity of Brn-3a(1). Here, we show that the opposite and antagonistic activities of Brn-3a(1) and Brn-3b(s) proteins are due to their different DNA binding properties; Brn-3a(1) but not Brn-3b(s) can form stable complexes with several octamer-related target DNA sequences. The presence of Brn-3b(s) completely inhibits the binding of Brn-3a(1) to DNA by preventing the formation of Brn-3a(1)-DNA complexes as well as by disrupting preformed complexes. Experiments with GST fusion proteins and in vitro binding studies suggest that the inhibition of Brn-3a(1) activity by Brn-3b(s) occurs via direct interaction of the two transcription factors in solution. Therefore, we hypothesize that Brn-3b(s) can act as a direct antagonist of Brn-3a(1) by inhibiting its DNA binding through the formation of an inactive hetero-oligomeric complex.

Patients with dementia involving families to maximize nursing care.

Incorporating family members in the care of patients with dementia provided pertinent psychosocial data, led to mutual decision-making regarding care, and produced changes in the responses of the residents with dementia, as well as in the family and nursing staff. The experimental group experienced increases in psychosocial nursing diagnoses with planning and interventions to meet the problems, more extensive problem description, and an active focus on interaction and change in the nurse's notes. As a result of collaborative nursing and family involvement, personal articles were brought from home; family collateral visits and interaction increased; families were more involved in the unit, medical center, and support groups; and p.r.n. medication use was decreased. As health-care technology prolongs the life of patients with chronic illness and sequelae such as dementia, nurses will need to continue to include families as collaborators in providing quality care.