Project description:To broadly identify genes regulated by Transparent Testa16 in Brassica napus In order to broadly identify genes regulated by BnTT16s, microarray technology was employed to compare gene expression levels in developing seeds (2-DAP) of Bntt16 RNAi and wild-type plants.
Project description:This series analyses germinating Arabidopsis seeds with both temporal and spatial detail, revealing two transcriptional phases that are separated with respect to testa rupture. Performed as part of the ERA-NET Plant Genomics grant vSEED. Arabidopsis seeds were dissected into four tissues at nine time-points during seed germination. The tissues were the combined micropylar and chalazal endosperm (MCE), the remaining endosperm (PE), the radicle and embryonic axis (RAD) and the cotyledons (COT). At testa and endosperm rupture the seeds were sampled in separate pre- and post-ruptured populations.
Project description:Invasive pneumococcal disease is preceded by asymptomatic colonization of the human nasopharynx by Streptococcus pneumoniae. Progression from colonization to invasion is a watershed in the host-pathogen interaction, and exposes the pneumococcus to markedly different microenvironments. This in turn, requires alterations in gene expression profile to adapt to the new niche. One apparent adaptive mechanism is reversible phase variation between “transparent” and “opaque” colony opacity phenotypes. Transparent phase variants colonize the nasopharynx more efficiently than opaque variants of the same strain, while opaque variants exhibit higher systemic virulence. Previous studies have reported quantitative differences in surface components such as the capsule, teichoic acid and certain surface proteins between the two phenotypes, but the underlying regulatory mechanism is not understood. In the present study, we found no differences in expression of key surface proteins between opaque and transparent variants of S. pneumoniae strain D39, but opaque cells produced five-fold more capsular polysaccharide. Subsequent microarray and real-time RT-PCR analysis showed no differences in capsule gene expression, but several genes involved in uridine monophosphate (UMP) biosynthesis were up-regulated in the opaque phenotype. This correlated with significant increases in the intracellular concentrations of both UMP and UDP-glucose, which are essential precursors for capsule biosynthesis. Our data suggest a novel mechanism for pneumococcal capsule regulation, in which rate-limiting precursor pathways are modulated rather than the capsule biosynthetic genes themselves. Keywords: Phase variants
Project description:This series analyses germinating Arabidopsis seeds with both temporal and spatial detail, revealing two transcriptional phases that are separated with respect to testa rupture. Performed as part of the ERA-NET Plant Genomics grant vSEED.
Project description:The associated files are mass spec data from individual fractions of mixed-bed ion exchange chromatography of native extract made from Arabidopsis thaliana (mutant ttg1-1, Koornneef (1981) Arabid. Inf. Serv. 18,45-51.) seeds. This is a hypomorph of the Transparent Testa Glabra 1 gene and was used instead of wild type because it is mucilage-less, facilitating protein extract preparation.
Project description:Components of the transcriptional machinery are dynamically compartmentalized by weak multivalent interactions, yet we know little about how specificity or selectivity of partitioning is achieved. Here we show that condensates composed of the intrinsically disordered region (IDR) of MED1 (MED1_IDR) selectively partition positive regulators of transcription(SPT6, CTR9, IWS1) with RNA Pol II while excluding negative regulators of transcription (NELF and HP1a).This selective compartmentalization by MED1_IDR is sufficient to activate transcription and is required for gene activation during a cell state transition. Surprisingly, the IDRs of partitioned proteins are sufficient to recapitulate selective compartmentalization. We find that IDR-mediated selective partitioning requires multivalent blocks of positive and negative charge on MED1_IDR and IDRs of partitioned proteins. The charge patterns required for partitioning are also required for gene activation. These findings demonstrate that proteins can be functionally compartmentalized by specific multivalent interactions driven by the charge patterning within disordered regions.
Project description:The nucleus contains diverse phase-separated condensates that compartmentalize and concentrate biomolecules with distinct physicochemical properties. Here we consider whether condensates concentrate small molecule cancer therapeutics such that their pharmacodynamic properties are altered. We found that antineoplastic drugs become concentrated in specific protein condensates in vitro and that this occurs through physicochemical properties independent of the drug target. This behavior was also observed in tumor cells, where drug partitioning influenced drug activity. Altering the properties of the condensate was found to impact the concentration and activity of drugs. These results suggest that selective partitioning and concentration of small molecules within condensates contributes to drug pharmacodynamics and that further understanding of this phenomenon may facilitate advances in disease therapy.