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Full-Text Articles in Other Biochemistry, Biophysics, and Structural Biology

Epigenetic Modification As An Enabling Mechanism For Leukemic Transformation, Vincent Sollars Aug 2012

Epigenetic Modification As An Enabling Mechanism For Leukemic Transformation, Vincent Sollars

Vincent E Sollars

Cancer is now thought of as a fundamentally genetic disease, in that changes in the genome result in aberrant gene expression of oncogenes and tumor suppressor genes to promote oncogenesis. However, with our increasing knowledge of gene regulation, it is becoming obvious that changes in nucleotide sequence are not the sole mechanism for eliciting changes in transcription. An additional layer of regulation of gene expression, called epigenetics, is now being realized as increasingly important in oncogenesis. Epigenetics is defined as non-sequence based changes in chromatin that elicit changes in gene expression that are propagated through mitosis and/or meiosis. The alleles …


Membrane Fusion Proteins Are Required For Oskar Mrna Localization In The Drosophila Egg Chamber, Douglas Ruden, Vincent Sollars, Xiaoyan Wang, Daisuke Mori, Marina Alterman, Xiangyi Lu Aug 2012

Membrane Fusion Proteins Are Required For Oskar Mrna Localization In The Drosophila Egg Chamber, Douglas Ruden, Vincent Sollars, Xiaoyan Wang, Daisuke Mori, Marina Alterman, Xiangyi Lu

Vincent E Sollars

We used a genetic screen in Drosophila to identify mutations which disrupt the localization of oskar mRNA during oogenesis. Based on the hypothesis that some cytoskeletal components which are required during the mitotic divisions will also be required for oskar mRNA localization during oogenesis, we designed the following genetic screen. We screened for P-element insertions in genes which slow down the blastoderm mitotic divisions. A secondary genetic screen was to generate female germ-line clones of these potential cell division cycle genes and to identify those which cause the mislocalization of oskar mRNA. We identified mutations in ter94 which disrupt the …


Diversity In Secreted Pla2-Iia Activity Among Inbred Mouse Strains That Are Resistant Or Susceptible To Apcmin/+ Tumorigenesis, Marina Markova, Revati Koratkar, Karen Silverman, Vincent Sollars, Melina Macphee-Pellini, Rhonda Walters, Juan Palazzo, Arthur Buchberg, Linda Siracusa, Steven Farber Aug 2012

Diversity In Secreted Pla2-Iia Activity Among Inbred Mouse Strains That Are Resistant Or Susceptible To Apcmin/+ Tumorigenesis, Marina Markova, Revati Koratkar, Karen Silverman, Vincent Sollars, Melina Macphee-Pellini, Rhonda Walters, Juan Palazzo, Arthur Buchberg, Linda Siracusa, Steven Farber

Vincent E Sollars

The secreted phospholipase A2 type IIA (Pla2g2a) gene was previously identified as a modifier of intestinal adenoma multiplicity in ApcMin/+ mice. To determine if intestinal secreted phospholipase A2 (sPLA2) activity was also attenuated in susceptible strains, we developed a sensitive assay to directly quantitate sPLA2 activity in the murine intestinal tract utilizing a fluorescent BODIPY-labeled phospholipid substrate. Here, we report assay conditions that distinguish between secreted and cytosolic PLA2 enzyme activities in extracts of intestinal tissue. The small intestine exhibited higher activity levels than the large intestine. Consistent with predictions from the sPLA …


A Drosophila Kinesin-Like Protein, Klp38b, Functions During Meiosis, Mitosis, And Segmentation, Douglas Ruden, Wei Cui, Vincent Sollars, Marina Alterman Aug 2012

A Drosophila Kinesin-Like Protein, Klp38b, Functions During Meiosis, Mitosis, And Segmentation, Douglas Ruden, Wei Cui, Vincent Sollars, Marina Alterman

Vincent E Sollars

We show that klp38B, isolated as a mutation that dominantly prolongs blastoderm mitotic cycles in Drosophila, encodes a Drosophila kinesin-like protein. Further genetic analyses show that Klp38B not only functions during mitosis, but is also required for meiosis and abdominal segmentation. Sequence comparisons suggest that Klp38B encodes an aminoterminal microtubule motor domain, a central a-helical coiled-coil domain, and a C-terminal globular domain. Evidence that Klp38B is required during meiosis is that flies transheterozygous for mutations in both klp38B and nod have a high frequency of 4th chromosome meiotic nondisjunction. Nod is a chromokinesin, a chromosome binding kinesin, that is believed …


17-N-Allylamino-17-Demethoxygeldanamycin Induces A Diverse Response In Human Acute Myelogenous Cells, Jennifer Napper, Vincent Sollars Aug 2012

17-N-Allylamino-17-Demethoxygeldanamycin Induces A Diverse Response In Human Acute Myelogenous Cells, Jennifer Napper, Vincent Sollars

Vincent E Sollars

The goal of this study was to ascertain the specific effects of 17-N-Allylamino-17-demethoxygeldanamycin (17-AAG) treatment in human acute myelogenous leukemia (AML). Four human leukemia cell lines were treated with varying doses of 17-AAG followed by analysis of toxicity, apoptosis, proliferation, and cell cycle. Cell cycle analysis revealed that the cells accumulate in G2/M phase within 96 hours of treatment, although the effect was not equivalent among the cell lines. p21, p53 expression and MDR1 activity were among the possible mechanisms uncovered for the differing responses. Exploiting these differences may allow for more effective combinatory treatments in patients with AML.


Evidence For An Epigenetic Mechanism By Which Hsp90 Acts As A Capacitor For Morphological Evolution, Vincent E. Sollars, Xiangyi Lu, Li Xiao, Xiaoyan Wang, Mark D. Garfinkel, Douglas M. Ruden Aug 2012

Evidence For An Epigenetic Mechanism By Which Hsp90 Acts As A Capacitor For Morphological Evolution, Vincent E. Sollars, Xiangyi Lu, Li Xiao, Xiaoyan Wang, Mark D. Garfinkel, Douglas M. Ruden

Vincent E Sollars

Morphological alterations have been shown to occur in Drosophila melanogaster when function of Hsp90 (heat shock 0-kDa protein 1α, encoded by Hsp83) is compromised during development1. Genetic selection maintains the altered phenotypes in subsequent generations1. Recent experiments have shown, however, that phenotypic variation still occurs in nearly isogenic recombinant inbred strains of Arabidopsis thaliana2. Using a sensitized isogenic D. melanogaster strain, iso-KrIf-1, we confirm this finding and present evidence supporting an epigenetic mechanism for Hsp90’s capacitor function, whereby reduced activity of Hsp90 induces a heritably altered chromatin state. The altered chromatin state is evidenced by ectopic expression of the morphogen …


The Epigenomic Viewpoint On Cellular Differentiation Of Myeloid Progenitor Cells As It Pertains To Leukemogenesis, Vincent E. Sollars Aug 2012

The Epigenomic Viewpoint On Cellular Differentiation Of Myeloid Progenitor Cells As It Pertains To Leukemogenesis, Vincent E. Sollars

Vincent E Sollars

The new millennium has brought with it a surge of research in the field of epigenetics. This has included advances in our understanding of stem cell characteristics and mechanisms of commitment to cell lineages prior to differentiation. The nature of stem cells is similar to that of malignant cells in that they have unlimited self-renewal and protection from apoptosis, leading researchers to suspect that stem cells are the target of oncogenesis. This review will explore the idea of how epigenetic control of gene expression may contribute to mechanisms controlling differentiation of myeloid progenitor cells and its importance to our understanding …


A High Omega-3 Fatty Acid Diet Has Different Effects On Early And Late Stage Myeloid Progenitors, Melinda Varney, James Buchanan, Yulia Dementieva, W. Hardman, Vincent Sollars Aug 2012

A High Omega-3 Fatty Acid Diet Has Different Effects On Early And Late Stage Myeloid Progenitors, Melinda Varney, James Buchanan, Yulia Dementieva, W. Hardman, Vincent Sollars

Vincent E Sollars

The effects of the polyunsaturated omega-3 (n-3) and omega-6 (n-6) fatty acids (FA) on hematopoiesis are complex in that both FA forms are processed into leukotrienes, eicosanoids, and prostaglandins, which can have independent effects. These FA have antagonistic effects in that n-6 FA prostaglandins tend to be pro-proliferative and pro-inflammatory, while the effects of n-3 FA prostaglandins are the opposite. We have previously shown that diets high in n-3 FA reduce the size of the middle to later stage myeloid progenitor compartment in FVB X sv129 F1hybrid mice. To assay the effects of high n-3 FA diets on earlier stages …