A motor independent requirement for dynein light chain in Caenorhabditis elegans meiotic synapsis.

The dynein motor complex is thought to aid in homolog pairing in many organisms by moving chromosomes within the nuclear periphery to promote and test homologous interactions. This precedes synaptonemal complex (SC) formation during homolog synapsis, which stabilizes homolog proximity during recombination. We observed that depletion of the dynein light chain (DLC-1) in Caenorhabditis elegans irreversibly prevents synapsis, causing an increase in off-chromatin formation of SC protein foci with increasing temperature.

Discovery of a Highly Potent and Novel Gambogic Acid Derivative as an Anticancer Drug Candidate.

Background And Purpose: Gambogic Acid (GA), a promising anti-cancer agent isolated from the resin of Garcinia species in Southeast Asia, exhibits high potency in inhibiting a wide variety of cancer cells' growth. Moreover, the fact that it is amenable to chemical modification makes GA an attractive molecule for the development of anti-cancer agents.

Methods: Gambogic acid-3-(4-pyrimidinyloxy) propyl ester (compound 4) was derived from the reaction between 4-hydroxypropoxy pyrimidine and GA.

Grincamycins I - K, Cytotoxic Angucycline Glycosides Derived from Marine-Derived Actinomycete Streptomyces lusitanus SCSIO LR32.

Three new angucycline glycosides, designated grincamycin I (1: ), J (2: ), and K (3: ), together with the known congener A-7884 (4: ), were isolated from marine-derived actinomycete SCSIO LR32. The structures of the new compounds were elucidated by comprehensive spectral data analysis. Compounds 2: and 4: exhibited antitumor activity against human cancer cells MDA-MB-435, MDA-MB-231, NCI-H460, HCT-116 and HepG2, and human normal breast epithelial cell MCF10A with IC values ranging from 0.

Apicidin Inhibited Proliferation and Invasion and Induced Apoptosis via Mitochondrial Pathway in Non-small Cell Lung Cancer GLC-82 Cells.

Background: Apicidin, as an inhibitor of histone deacetylase, showed a wide range of antiproliferative activity against various cancer cell lines. Apicidin has also been reported to induce apotosis via Fas/Fas ligand. Yet few studies have been focused on mitochondrial pathway for its anti-tumor activity.

The Drosophila Helicase Maleless (MLE) is Implicated in Functions Distinct From its Role in Dosage Compensation.

Helicases are ubiquitous enzymes that unwind or remodel single or double-stranded nucleic acids, and that participate in a vast array of metabolic pathways. The ATP-dependent DEXH-box RNA/DNA helicase MLE was first identified as a core member of the chromatin remodeling MSL complex, responsible for dosage compensation in Drosophila males. Although this complex does not assemble in females, MLE is present.

Topoisomerase II plays a role in dosage compensation in Drosophila.

In Drosophila, dosage compensation is mediated by the MSL complex, which binds numerous sites on the X chromosome in males and enhances the transcriptional rate of a substantial number of X-linked genes. We have determined that topoisomerase II (Topo II) is enriched on dosage compensated genes, to which it is recruited by association with the MSL complex, in excess of the amount that is present on autosomal genes with similar transcription levels. Using a plasmid model, we show that Topo II is required for proper dosage compensation and that compensated chromatin is topologically different from non-compensated chromatin.

Distinct contributions of MSL complex subunits to the transcriptional enhancement responsible for dosage compensation in Drosophila.

The regulatory mechanism of dosage compensation is the paramount example of epigenetic regulation at the chromosomal level. In Drosophila, this mechanism, designed to compensate for the difference in the dosage of X-linked genes between the sexes, depends on the MSL complex that enhances the transcription of the single dose of these genes in males. We have investigated the function of various subunits of the complex in mediating dosage compensation.

Role of the ATPase/helicase maleless (MLE) in the assembly, targeting, spreading and function of the male-specific lethal (MSL) complex of Drosophila.

Background: The male-specific lethal (MSL) complex of Drosophila remodels the chromatin of the X chromosome in males to enhance the level of transcription of most X-linked genes, and thereby achieve dosage compensation. The core complex consists of five proteins and one of two non-coding RNAs. One of the proteins, MOF (males absent on the first), is a histone acetyltransferase that specifically acetylates histone H4 at lysine 16.

A plasmid model system shows that Drosophila dosage compensation depends on the global acetylation of histone H4 at lysine 16 and is not affected by depletion of common transcription elongation chromatin marks.

Dosage compensation refers to the equalization of most X-linked gene products between males, which have one X chromosome and a single dose of X-linked genes, and females, which have two X's and two doses of such genes. We developed a plasmid-based model of dosage compensation that allows new experimental approaches for the study of this regulatory mechanism. In Drosophila melanogaster, an enhanced rate of transcription of the X chromosome in males is dependent upon the presence of histone H4 acetylated at lysine 16.