Insights into the cotranscriptional and translational control mechanisms of the Escherichia coli tbpA thiamin pyrophosphate riboswitch.

Riboswitches regulate gene expression by modulating their structure upon metabolite binding. These RNA orchestrate several layers of regulation to achieve genetic control. Although Escherichia coli riboswitches modulate translation initiation, several cases have been reported where riboswitches also modulate mRNA levels.

Non-neovascular age-related macular degeneration with subretinal fluid.

Purpose: To evaluate the various patterns of subretinal fluid (SRF) in eyes with age-related macular degeneration (AMD) in the absence of macular neovascularisation (MNV) and to assess the long-term outcomes in these eyes.

Methods: This retrospective study included only eyes with non-neovascular AMD and associated SRF. Eyes with evidence of MNV were excluded.

Maestro of regulation: Riboswitches orchestrate gene expression at the levels of translation, transcription and mRNA decay.

Riboswitches are RNA regulators that control gene expression by modulating their structure in response to metabolite binding. The study of mechanisms by which riboswitches modulate gene expression is crucial to understand how riboswitches are involved in maintaining cellular homeostasis. Previous reports indicate that riboswitches can control gene expression at the level of translation, transcription or mRNA decay.

Transcriptional pausing at the translation start site operates as a critical checkpoint for riboswitch regulation.

On the basis of nascent transcript sequencing, it has been postulated but never demonstrated that transcriptional pausing at translation start sites is important for gene regulation. Here we show that the Escherichia coli thiamin pyrophosphate (TPP) thiC riboswitch contains a regulatory pause site in the translation initiation region that acts as a checkpoint for thiC expression. By biochemically probing nascent transcription complexes halted at defined positions, we find a narrow transcriptional window for metabolite binding, in which the downstream boundary is delimited by the checkpoint.

Protein localization in the human eye and genetic screen of opticin.

The opticin (OPTC) gene encodes a protein that is a member of the small leucine-rich repeat protein (SLRP) family. OPTC is located on chromosome 1q31-q32 within an age-related macular degeneration (AMD) susceptibility locus. We have developed an affinity-purified N-terminal anti-opticin antibody and used it to examine opticin expression in human eye tissues.