Dr Rosemary Cater

@rosemaryjcater.bsky.social

Senior Research Fellow and Group Leader at @IMBatUQ Interested in the structural and functional biology of transporters 🇦🇺🔬

Congratulations to the Cater Lab's first ever graduate Parteek! Bachelor of Advanced Scince with First Class Honours - we are SO proud of you! Looking forward to another year of fun in the lab together in 2026! 🎓🔬🧪✨

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👕✨ Design the next Lorne Protein Conference T-shirt! Entries close 17 Oct – don’t miss your chance to show off your creativity and cement your place in the history of Lorne Proteins 🤓 👉 Submit your design-see the link below... 📢 And don’t forget to submit your abstract by 24 Oct! #LorneProteins

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Add it to your calendars! Register and submit your abstract for ASBMB this month! 🗓️📃🧬🧫🔬

Australian Society for Biochemistry and Molecular Biology - 2025@asbmbaus.bsky.social · last yr.

Abstract submissions are now open! Submit your abstracts: www.asbmb2025.com.au/2025-call-fo... Abstract deadline: 5pm AEST on Monday 30 June 2025 *Note: You must have completed and paid registration by this time to have your submission considered. Early bird deadline: Friday 1 August 2025

Session 10 Ibrahim Cissé-Super-res imaging of transcription. Cooperativity in weak & transient biological interactions. PolII clustering in a cell nucleus w STORM. Limitations for weak and transient interactions. Lightsheet microscopy to follow polymerase condensates & gene bursts #LorneProteins2025

High resolution in fixed cells, but temporal events - transient, sub diffraction clusters in live mammalian cells. -ve feedback - 4-5 polymerase load, clusters are released. Cells can hold clusters longer to increase transcriptional events. Dual colour super resolution. TcPALM. Measure active burst, estimate RNAs and correlate with cluster lifetime. Enhancer, mediator, PolII - Mediator and PolII in stem cells. Short lived 11 s. Subset large clusters 300-400 nm in size, long lived 10s of minutes. Lattice lightsheet. 3d, time lapse, 10s of minutes, a full nucleus every 15s or so.

Some clusters fuse to merge content. In vivo condensates with liquid like properties. Condensate proximity to Sox2 promoter correlates to mRNA burst intensity. Du et al, Cell, 2024.

Higher burst size, higher frequency of burst events. 1.5-2 fold higher proximal to a PolII condensate.

Anticorrelation between distance and burst size. When condensate contacts enhancer and generates. If superenhancer is distal from condensate, then no burst.

Mediator/PolII, Superenhancer DNA, nascent mRNA in 3 colours. Movie of condensate moving in to contact the superenhancer, Gene promoter active and mRNA increases. 

Is the condensate/superenhancer contact active? Yes, cohesion required to loop DNA - precise architecture of the DNA to achieve a burst. Cohesion loops DNA and stops at an enhancer element upstream of the promoter.

Lee et al 2024, Condensates - complex, liquid droplets? Proximity mini turbo ID? Accumulate any cargo of interest to be concentrated in the condensate. Turn on blue light and generate condensate localisation? Light induced targeting of endogenous condensates.

Cargo-miniturbo-ID-GFP blue light on, accumulates in condensate, biotinylation accumulating. LiTEC with BioID for proteomics on condensates. Some missing... Chimeric mining. Pass droplets through mass spec - often ignore low intensity peaks. Looked for background peaks. More to follow up..

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ARC says they’ll release the Discovery Projects 2025 outcomes tomorrow. Recently, outcomes announcements have tended to happen at/around 11am Canberra time. My bot will pick up the announcement in RMS’s database and post immediately. Good luck!

Screenshot of a tweet from the ARC saying they’ll announce DP25 grant outcomes tomorrow (Tuesday 26 Nov).