Primary Malignant Melanoma of the Breast Presenting as a Breast Abscess: A Case Report.

Primary malignant melanoma in breast parenchyma (PMB) is an extremely rare disease, and the most common presentation is a palpable breast lump. To the best of our knowledge, a case of PMB presenting as a breast abscess has not been reported in English literatures. We present a case of PMB that manifested as a recurrent breast abscess in a 71-year-old woman. On MRI, an enhancing solid mass with a cystic or necrotic portion was revealed with some high signal intensities on precontrast-enhanced T1-weighted images and a dark rim on T2-weighed images. The MRI features played a pivotal role in identifying the underlying malignant condition and making an accurate diagnosis of this rare case of PMB with unusual clinical presentation.

Identifying Small Bowel Gastrointestinal Stromal Tumor as the Culprit Lesion in Obscure Gastrointestinal Bleeding: Emphasis on Angiographic Findings.

Gastrointestinal stromal tumors (GISTs) are not uncommon and often cause gastrointestinal bleeding. GISTs occurring in the small intestine are occasionally difficult to identify by endoscopy and CT. In this case, the patient underwent CT three times before surgery, and the lesion was found to be located in a different area of the abdominal cavity on each CT scan. Moreover, the lesion was missed in the first two CT images because it was difficult to distinguish it from the nearby collapsed small intestine. The lesion was eventually detected through angiography; however, the correct diagnosis and treatment were delayed for 3 years because it was mistaken for a vascular malformation, which is the most common cause of obscure GI bleeding in elderly patients. This report emphasizes the need for interventional radiologists to be updated and vigilant of the angiographic features of GISTs to make an accurate diagnosis and establish a management strategy.

DREB2C interacts with ABF2, a bZIP protein regulating abscisic acid-responsive gene expression, and its overexpression affects abscisic acid sensitivity.

ABF2 is a basic leucine zipper protein that regulates abscisic acid (ABA)-dependent stress-responsive gene expression. We carried out yeast two-hybrid screens to isolate genes encoding ABF2-interacting proteins in Arabidopsis (Arabidopsis thaliana). Analysis of the resulting positive clones revealed that two of them encode an AP2 domain protein, which is the same as AtERF48/DREB2C. This protein, which will be referred to as DREB2C, could bind C-repeat/dehydration response element in vitro and possesses transcriptional activity. To determine its function, we generated DREB2C overexpression lines and investigated their phenotypes. The transgenic plants were ABA hypersensitive during germination and seedling establishment stages, whereas primary root elongation of seedlings was ABA insensitive, suggesting developmental stage dependence of DREB2C function. The DREB2C overexpression lines also displayed altered stress response; whereas the plants were dehydration sensitive, they were freezing and heat tolerant. We further show that other AP2 domain proteins, DREB1A and DREB2A, interact with ABF2 and that other ABF family members, ABF3 and ABF4, interact with DREB2C. Previously, others demonstrated that ABF and DREB family members cooperate to activate the transcription of an ABA-responsive gene. Our result implies that the cooperation of the two classes of transcription factors may involve physical interaction.

Arabidopsis calcium-dependent protein kinase AtCPK32 interacts with ABF4, a transcriptional regulator of abscisic acid-responsive gene expression, and modulates its activity.

The phytohormone abscisic acid (ABA) regulates stress-responsive gene expression during vegetative growth. The ABA regulation of many genes is mediated by a subfamily of basic leucine zipper class transcription factors referred to as ABFs (i.e. ABF1-ABF4), whose transcriptional activity is induced by ABA. Here we show that a calcium-dependent protein kinase is involved in the ABA-dependent activation process. We carried out yeast two-hybrid screens to identify regulatory components of ABF4 function and isolated AtCPK32 as an ABF4-interacting protein. AtCPK32 has autophosphorylation activity and can phosphorylate ABF4 in vitro. Mutational analysis indicated that serine-110 of ABF4, which is highly conserved among ABF family members, may be phosphorylated by AtCPK32. The serine-110 residue is essential for ABF4-AtCPK32 interaction, and transient expression assay revealed that it is also required for the normal transcriptional function of ABF4. The expression patterns and subcellular localization of AtCPK32 are similar to those of ABF4. Furthermore, its overexpression affects both ABA sensitivity and the expression of a number of ABF4-regulated genes. Together, our data demonstrate that AtCPK32 is an ABA signaling component that regulates the ABA-responsive gene expression via ABF4.

ARIA, an Arabidopsis arm repeat protein interacting with a transcriptional regulator of abscisic acid-responsive gene expression, is a novel abscisic acid signaling component.

Arabidopsis (Arabidopsis thaliana) genome contains more than 90 armadillo (arm) repeat proteins. However, their functions are largely unknown. Here, we report that an Arabidopsis arm repeat protein is involved in abscisic acid (ABA) response. We carried out two-hybrid screens to identify signaling components that modulate ABA-responsive gene expression. Employing a transcription factor, ABF2, which controls the ABA-dependent gene expression via the G-box type ABA-responsive elements, we isolated an arm repeat protein. The ABF2-interacting protein, designated as ARIA (arm repeat protein interacting with ABF2), has another conserved sequence motif, BTB/POZ (broad complex, tramtrak, and bric-a-brac/poxvirus and zinc finger) domain, in the C-terminal region. The physiological relevance of ABF2-ARIA interaction was supported by their similar expression patterns and similar subcellular localization. Plants overexpressing ARIA are hypersensitive to ABA and high osmolarity during germination and insensitive to salt during subsequent seedling growth. By contrast, an ARIA knockout mutant exhibits ABA and glucose insensitivities. Changes in the expression levels of several ABF2-regulated genes were also observed in ARIA overexpression lines, indicating that ARIA modulates the transcriptional activity of ABF2. Together, our data indicate that ARIA is a positive regulator of ABA response.

Arabidopsis basic leucine zipper proteins that mediate stress-responsive abscisic acid signaling.

The phytohormone abscisic acid (ABA) plays an essential role in adaptive stress responses. The hormone regulates, among others, the expression of numerous stress-responsive genes. From various promoter analyses, ABA-responsive elements (ABREs) have been determined and a number of ABRE binding factors have been isolated, although their in vivo roles are not known. Here we report that the ABRE binding factors ABF3 and ABF4 function in ABA signaling. The constitutive overexpression of ABF3 or ABF4 in Arabidopsis resulted in ABA hypersensitivity and other ABA-associated phenotypes. In addition, the transgenic plants exhibited reduced transpiration and enhanced drought tolerance. At the molecular level, altered expression of ABA/stress-regulated genes was observed. Furthermore, the temporal and spatial expression patterns of ABF3 and ABF4 were consistent with their suggested roles. Thus, our results provide strong in vivo evidence that ABF3 and ABF4 mediate stress-responsive ABA signaling.