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Rog lab at the University of Utah

@theroglab.bsky.social

1.1K followers 899 following 33 posts

Cell biology of chromosomes in meiosis 🏳️‍🌈

Rog lab at the University of Utah @theroglab.bsky.social · 15/01/2025

Finally, we used our kinetic information to derive the total number of DSBs. We found an average of 40 DSBs per nucleus in wild-type meiosis suggesting a ratio of 7:1 of DSBs to crossovers, and more DSBs in mutant scenarios.

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Rog lab at the University of Utah @theroglab.bsky.social · 15/01/2025

Second, strand invasion kinetics were similar for repair events templated by the homolog versus the sister. This was surprising, since a leading hypothesis is that DSBs that don't find the homologs stall and are only repaired at the end of meiosis using the sister chromatid.

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Rog lab at the University of Utah @theroglab.bsky.social · 15/01/2025

We made 3 crucial findings. First, we found that most repair events finish the strand-invasion step in 1-2 hours. This is true for both endogenous (SPO-11-induced) and irradiation-induced DSBs.

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Rog lab at the University of Utah @theroglab.bsky.social · 15/01/2025

New preprint from the lab! We defined the kinetics of strand invasion during meiosis in C. elegans. Great work from Antonia, Henry and Divya. www.biorxiv.org/content/10.1...

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Rog lab at the University of Utah @theroglab.bsky.social · 01/07/2024

In both nematode, Skp1 is not only necessary for assembly of the SC onto chromosomes - without dimerization-competent Skp1, SC proteins are absent.

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Rog lab at the University of Utah @theroglab.bsky.social · 01/07/2024

Lisa turned to the distantly related nematode P. pacificus, and found that the answer is a resounding ‘yes’. Ppa-SKR-1 localize to the middle of the SC, and a conserved dimerization interface in Skp1 is specifically required for SC assembly in Pristi, as it is in elegans.

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Rog lab at the University of Utah @theroglab.bsky.social · 01/07/2024

That has crucial implications: ZHP-3 can sample the entire 6um chromosome in tens of minutes, whereas SYP-3 cannot. By extension, ZHP-3 is capable of efficiently transducing a crossover signal, whereas SYP-3 would be unlikely to.

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Rog lab at the University of Utah @theroglab.bsky.social · 01/07/2024

The second important finding came from comparing the diffusion of an SC component (SYP-3) vs a regulator of crossovers (ZHP-3). ZHP-3 diffuses 4-9 times faster than SYP-3 (depending on meiotic stage).

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Rog lab at the University of Utah @theroglab.bsky.social · 01/07/2024

However, a crucial piece of this model has not been tested: do molecules diffuse within the SC? Lexy directly tested that. By sparsely labeling SC components and crossover regulators, she was able to observe single molecules in live gonads.

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Rog lab at the University of Utah @theroglab.bsky.social · 01/07/2024

Our data revealed sliding of cohesin on DNA (presumably loop extrusion); positioning of nucleosomes; and, AFAIK, the first binding patterns of cohesins in the rDNA locus. Much more data inside.

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Rog lab at the University of Utah @theroglab.bsky.social · 01/07/2024

We also performed a CheC-PLS on isolated nuclei, using Rec8-GFP and nanobodies targeted to GFP and tethered to a methyltransferase. (This variation is related to recently published techniques like DiMeLo-seq and SAMOSA). cc @astraight.bsky.social

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Rog lab at the University of Utah @theroglab.bsky.social · 01/07/2024

#1: CheC-PLS (pronounced ‘check, please’) is a new genomic technique. It relates to ChIP, but adds 4 crucial features: 1. contiguity (how distant events are regulated) 2. history (where a protein has been) 3. heterogeneity (single cell data) 4. context (mapping repeats).

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Rog lab at the University of Utah @theroglab.bsky.social · 12/12/2023

The story starts with a saturated suppressor screen for a temperature-sensitive mutation that destabilizes the SC. Lisa identified dozens of suppressors, that all mapped to three short stretches in SC proteins.

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