Development of 6-amido-4-aminoisoindolyn-1,3-diones as p70S6K1 inhibitors and potential breast cancer therapeutics.

Introduction: Many breast cancer therapeutics target the PI3K/AKT/mTOR oncogenic pathway. Development of resistance to the therapeutics targeting this pathway is a frequent occurrence. Therapeutics targeting p70S6K1, a downstream member of this pathway, have recently gained importance due to its critical role in all types of breast cancer and its status as a prognostic marker.

Involvement of co-repressor LUH and the adapter proteins SLK1 and SLK2 in the regulation of abiotic stress response genes in Arabidopsis.

Background: During abiotic stress many genes that are important for growth and adaptation to stress are expressed at elevated levels. However, the mechanisms that keep the stress responsive genes from expressing under non stress conditions remain elusive. Recent genetic characterization of the co-repressor LEUNIG_HOMOLOG (LUH) and transcriptional adaptor proteins SEUSS-LIKE1 (SLK1) and SLK2 have been proposed to function redundantly in diverse developmental processes; however their function in the abiotic stress response is unknown.

Transformation and analysis of tobacco plant var Petit havana with T-urf13 gene under anther-specific TA29 promoter.

T-urf13, a well-documented cms-associated gene from maize, has been shown to render methomyl sensitivity to heterologous systems like rice, yeast and bacteria when expressed constitutively. Since these transgenic plants were fertile, it was hypothesized that T-urf13 gene if expressed in anthers may result in male sterility that could be used for hybrid seed production. Hence, this work was aimed at analysing whether T-urf13 gene when expressed in anthers can result in male sterile plants or requires methomyl treatment to cause male sterility (controllable).

Distinctive core histone post-translational modification patterns in Arabidopsis thaliana.

Post-translational modifications of histones play crucial roles in the genetic and epigenetic regulation of gene expression from chromatin. Studies in mammals and yeast have found conserved modifications at some residues of histones as well as non-conserved modifications at some other sites. Although plants have been excellent systems to study epigenetic regulation, and histone modifications are known to play critical roles, the histone modification sites and patterns in plants are poorly defined.

Control of DNA methylation and heterochromatic silencing by histone H2B deubiquitination.

Epigenetic regulation involves reversible changes in DNA methylation and/or histone modification patterns. Short interfering RNAs (siRNAs) can direct DNA methylation and heterochromatic histone modifications, causing sequence-specific transcriptional gene silencing. In animals and yeast, histone H2B is known to be monoubiquitinated, and this regulates the methylation of histone H3 (refs 10, 11).

The DNA glycosylase/lyase ROS1 functions in pruning DNA methylation patterns in Arabidopsis.

The Arabidopsis DNA glycosylase/lyase ROS1 participates in active DNA demethylation by a base-excision pathway. ROS1 has been shown to be required for demethylating a transgene promoter. To determine the function of ROS1 in demethylating endogenous loci, we carried out bisulfite-sequencing analysis of several transposons and other genes in the ros1 mutant.

APETALA1 and SEPALLATA3 interact with SEUSS to mediate transcription repression during flower development.

The transcriptional repression of key regulatory genes is crucial for plant and animal development. Previously, we identified and isolated two Arabidopsis transcription co-repressors LEUNIG (LUG) and SEUSS (SEU) that function together in a putative co-repressor complex to prevent ectopic AGAMOUS (AG) transcription in flowers. Because neither LUG nor SEU possesses a recognizable DNA-binding motif, how they are tethered to specific target promoters remains unknown.

Transcriptional repression of target genes by LEUNIG and SEUSS, two interacting regulatory proteins for Arabidopsis flower development.

Transcription repression plays important roles in preventing crucial regulatory proteins from being expressed in inappropriate temporal or spatial domains. LEUNIG (LUG) and SEUSS (SEU) normally act to prevent ectopic expression of the floral homeotic gene AGAMOUS in flowers. LUG encodes a protein with sequence similarities to the yeast Tup1 corepressor.