Genome-wide gene expression responses to experimental manipulation of Saccharomyces cerevisiae repressor activator protein 1 (Rap1) expression level

Precise regulation of transcription in gene expression is critical for all aspects of normal organism form, fitness, and function and even minor alterations in the level, location, and timing of gene expression can result in phenotypic variation within and between species including evolutionary innovations and human disease states. Eukaryotic transcription is regulated by a complex interplay of multiple factors working both at a physical and molecular levels influencing this process. In Saccharomyces cerevisiae, the TF with the greatest number of putative regulatory targets is the essential gene Repressor Activator Protein 1 (RAP1). While much is known about the roles of Rap1 in gene regulation and numerous cellular processes, the response of Rap1 target genes to systematic titration of RAP1 expression level remains unknown. To fill this knowledge gap, we used a strain with a tetracycline-titratable promoter replacing wild-type regulatory sequences of RAP1 to systematically reduce the expression level of RAP1 and followed this with RNA sequencing (RNA-seq) to measure genome-wide gene expression responses. Previous research indicated that Rap1 plays a significant regulatory role in particular groups of genes including telomere-proximal genes, homothallic mating (HM) loci, glycolytic genes, DNA repair genes, and ribosomal protein genes; therefore, we focused our analyses on these groups and downstream targets to determine how they respond to reductions in RAP1 expression level. Overall, despite being known as both an activator and as a repressor of its target genes, we found that Rap1 acts as an activator for more target genes than as a repressor. Additionally, we found that Rap1 functions as an activator of ribosomal protein genes and a repressor of the silent mating locus genes consistent with predictions from the literature. Unexpectedly, we found that Rap1 functions as a repressor of glycolytic enzyme genes contrary to prior reports of it having the opposite effect. We also compared the expression of RAP1 to five different genes related to DNA repair pathway and found that decreasing RAP1 downregulated four of those five genes. Finally, we found no effect of RAP1 depletion on telomere-proximal genes despite its functioning to silence telomeric repeat-containing RNAs. Together our results enrich our understanding of this important transcriptional regulator. The graphical abstract is provided as a supplementary fig. (S-Fig 1).

Vaginal ulcerations due to lithium carbonate therapy

A twenty-nine-year-old woman who had been taking lithium carbonate for seven years experienced ulcerated lesions of the vaginal mucosa and acneiform eruption on both thighs. Histopathologic appearance of the skin biopsy specimens was consistent with lichenoid cutaneous changes. The cutaneous lesions cleared when use of the drug was discontinued.

The establishment of an ovum donation program using a simple fixed-dose estrogen-progesterone replacement regimen

Most ovum donation (OD) programs involve cycle synchronization between recipient and donor for normally cycling recipients and a complex estrogen-progesterone replacement regimen for recipients with ovarian failure. In 1987, Serhal and Craft (1) suggested the use of a fixed-dose estrogen-progesterone regimen for recipients who were normally ovulatory and to those with ovarian failure. Following this protocol, and simplifying it still, the authors administered 6 mg estradiol valerate (E2) daily orally starting on day 2-6 of induced withdrawal bleeding, augmented with 100 mg progesterone in ethyl oleate (P) intramuscularly daily, starting any time between 4 days prior to and the day of oocyte pickup. All recipients underwent embryo transfer at a 2-pronuclei (2PN)-10-cell stage. A group of 21 patients underwent 26 treatment cycles, resulting in 16 pregnancies. Twelve of the patients gave birth, one to triplets, two to twins, and nine to singletons. Four patients miscarried in the first trimester of pregnancy.

Hypotensive effect of bromocriptine in normal eyes

The effect of a single oral dose of 2.5 mg Bromocriptine on intraocular pressure over a 12 hour period in a group of 20 puerperal women with normal eyes, is reported. Intraocular pressure was significantly reduced, the maximal response being 3-4 hours after administration. Possible explanations for the reducing effect of Bromocriptine on intraocular pressure are discussed.

Diffuse unilateral subacute neuroretinitis

In December 1980, a 26-year-old black man came to the Washington Hospital Center Eye Clinic with a unilateral decrease in visual acuity, vitreous inflammation, optic disk pallor, and a degenerated retinal pigment epithelium. A motile subretinal worm was subsequently found. Unlike an earlier series of 18 patients with diffuse unilateral subacute neuroretinitis reported by other authors, this patient exhibited eosinophilia and a highly positive ELISA for Toxocara.

Light intensity and visual acuity following cataract surgery

The authors analyzed 310 cataract operations that were randomly distributed between two operating rooms, each containing a microscope with different light intensities. The light intensity of one microscope was almost threefold greater than the other. One hundred seventy-seven patients were excluded from this study because of medical or ocular problems that might affect visual acuity. The remaining 133 patients are the subjects of this paper. Seventy-one were operated upon under high intensity light, and 62 were subjected to lower illumination in the operating room. Visual acuity after operation was correlated with type of microscope, age, sex, method of cataract extraction, and use of intraocular lenses. Reduced visual acuity (20/40 or worse) was consistently more common with high intensity light and with increasing age. Further investigation is recommended to establish the cause of this reduced acuity.