Measuring Chromosome Pairing During Homologous Recombination in Yeast.

The precise organization of the genome inside the cell nucleus is vital to many cell functions including gene expression, cell division, and DNA repair. Here we describe a method to measure pairing of DNA loci during homologous recombination (HR) at a site-specific double-strand break (DSB) in Saccharomyces cerevisiae. This method utilizes a chromosome tagging system in diploid yeast cells to visualize both the DNA at the break site and the homologous DNA that serves as a repair template.

DNA damage triggers increased mobility of chromosomes in G1-phase cells.

During S phase in , chromosomal loci become mobile in response to DNA double-strand breaks both at the break site (local mobility) and throughout the nucleus (global mobility). Increased nuclear exploration is regulated by the recombination machinery and the DNA damage checkpoint and is likely an important aspect of homology search. While mobility in response to DNA damage has been studied extensively in S phase, the response in interphase has not, and the question of whether homologous recombination proceeds to completion in G1 phase remains controversial.

Rad5 dysregulation drives hyperactive recombination at replication forks resulting in cisplatin sensitivity and genome instability.

The postreplication repair gene, HLTF, is often amplified and overexpressed in cancer. Here we model HLTF dysregulation through the functionally conserved Saccharomyces cerevisiae ortholog, RAD5. Genetic interaction profiling and landscape enrichment analysis of RAD5 overexpression (RAD5OE) reveals requirements for genes involved in recombination, crossover resolution, and DNA replication.

Increased chromosomal mobility after DNA damage is controlled by interactions between the recombination machinery and the checkpoint.

During homologous recombination, cells must coordinate repair, DNA damage checkpoint signaling, and movement of chromosomal loci to facilitate homology search. In , increased movement of damaged loci (local mobility) and undamaged loci (global mobility) precedes homolog pairing in mitotic cells. How cells modulate chromosome mobility in response to DNA damage remains unclear.

CRISPR-Mediated Base Editing Enables Efficient Disruption of Eukaryotic Genes through Induction of STOP Codons.

Standard CRISPR-mediated gene disruption strategies rely on Cas9-induced DNA double-strand breaks (DSBs). Here, we show that CRISPR-dependent base editing efficiently inactivates genes by precisely converting four codons (CAA, CAG, CGA, and TGG) into STOP codons without DSB formation. To facilitate gene inactivation by induction of STOP codons (iSTOP), we provide access to a database of over 3.

A Synthetic Dosage Lethal Genetic Interaction Between CKS1B and PLK1 Is Conserved in Yeast and Human Cancer Cells.

The CKS1B gene located on chromosome 1q21 is frequently amplified in breast, lung, and liver cancers. CKS1B codes for a conserved regulatory subunit of cyclin-CDK complexes that function at multiple stages of cell cycle progression. We used a high throughput screening protocol to mimic cancer-related overexpression in a library of Saccharomyces cerevisiae mutants to identify genes whose functions become essential only when CKS1 is overexpressed, a synthetic dosage lethal (SDL) interaction.

Integration of palliative care into emergency medicine: the Improving Palliative Care in Emergency Medicine (IPAL-EM) collaboration.

Background: Emergency department (ED) providers commonly care for seriously ill patients who suffer from advanced, chronic, life-limiting illnesses in addition to those that are acutely ill or injured. Both the chronically ill and those who present in extremis may benefit from application of palliative care principles.

Case Report: We present a case highlighting the opportunities and need for better integration of emergency medicine and palliative care.

The ethics of health care reform: impact on emergency medicine.

The recent enactment of the Patient Protection and Affordable Care Act (ACA) of 2010, and the ongoing debate over reform of the U.S. health care system, raise numerous important ethical issues.

Bleeding scrotal arteriovenous malformation.

Background: Arteriovenous malformation (AVM) of the scrotum has, to our knowledge, been reported fewer than 10 times in the medical literature. It may be of congenital or post-traumatic etiology and has been reported to present with spontaneous bleeding.

Case Report: A case of a spontaneously bleeding scrotal AVM that developed after remote trauma is presented.