TOF1 and RRM3 reveal a link between gene silencing and the pausing of replication forks.

Eukaryotic DNA replication is accompanied by the disassembly and reassembly of nucleosomes and the transmission of epigenetic marks to the newly assembled chromatids. Several histone chaperones, including CAF-1 and Asf1p, are central to these processes. On the other hand, replication forks pause at numerous positions throughout the genome, but it is not known if and how this pausing affects the reassembly and maintenance of chromatin structures.

Evaluation of drug-free methods for the detection of gene silencing in .

Multiple studies in have measured the levels of gene silencing by inserting the gene at various loci and selecting against -expressing cells by 5-flouroorotic acid (5-FOA). However, 5-FOA affects the cellular pools of dNTPs and can produce side effects. To circumvent this issue, we and others have introduced drug-free techniques to detect silent and active gene states.

Dbf4-Dependent Kinase: DDK-ated to post-initiation events in DNA replication.

Dbf4-Dependent Kinase (DDK) has a well-established essential role at origins of DNA replication, where it phosphorylates and activates the replicative MCM helicase. It also acts in the response to mutagens and in DNA repair as well as in key steps during meiosis. Recent studies have indicated that, in addition to the MCM helicase, DDK phosphorylates several substrates during the elongation stage of DNA replication or upon replication stress.

Variation, Variegation and Heritable Gene Repression in .

Phenotypic heterogeneity provides growth advantages for a population upon changes of the environment. In , such heterogeneity has been observed as "on/off" states in the expression of individual genes in individual cells. These variations can persist for a limited or extended number of mitotic divisions.

Gene repression in S. cerevisiae-looking beyond Sir-dependent gene silencing.

Gene silencing by the SIR (Silent Information Region) family of proteins in S. cerevisiae has been extensively studied and has served as a founding paradigm for our general understanding of gene repression and its links to histone deacetylation and chromatin structure. In recent years, our understanding of other mechanisms of gene repression in S.

Dysfunctional CAF-I reveals its role in cell cycle progression and differential regulation of gene silencing.

Chromatin Assembly Factor I (CAF-I) plays a central role in the reassembly of H3/H4 histones during DNA replication. In CAF-I is not essential and its loss is associated with reduced gene silencing at telomeres and increased sensitivity to DNA damage. Two kinases, Cyclin Dependent Kinase (CDK) and Dbf4-Dependent Kinase (DDK), are known to phosphorylate the Cac1p subunit of CAF-I, but their role in the regulation of CAF-I activity is not well understood.

Histone chaperones and the Rrm3p helicase regulate flocculation in S. cerevisiae.

Background: Biofilm formation or flocculation is a major phenotype in wild type budding yeasts but rarely seen in laboratory yeast strains. Here, we analysed flocculation phenotypes and the expression of FLO genes in laboratory strains with various genetic backgrounds.

Results: We show that mutations in histone chaperones, the helicase RRM3 and the Histone Deacetylase HDA1 de-repress the FLO genes and partially reconstitute flocculation.

Cellular immune responses to recombinant Mycobacterium bovis BCG constructs expressing major antigens of region of difference 1 of Mycobacterium tuberculosis.

Besides being the most widely used vaccine directed against tuberculosis (TB) worldwide, Mycobacterium bovis BCG is also the most controversial vaccine in current use. Its protective efficacy varies widely in different parts of the world. One approach to improving the current BCG vaccine might be to produce recombinant BCG strains that express major antigens encoded by genes that are present in the M.