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Reposted by Blake Hernandez

Spirochrome @spirochrome.com · Jun 23

Let's start the week with this movie kindly shared by @loxstoplox.bsky.social
The movie shows a mouse embryo labeled with Formin-2-GFP and SPY650-DNA during nuclear envelope breakdown. Note the nuclear dilution of Formin-2-GFP immediately before the SPY650-DNA labeled chromosomes start compaction.

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Reposted by Blake Hernandez

Science Magazine @science.org · May 30

New findings in Science demonstrate that successful mitosis may draw on more mechanisms than commonly assumed.

Learn more in this #SciencePerspective: scim.ag/4dFbqnp

Rewriting the rules of cell division

Microtubules get help from actin filaments during mitosis

scim.ag

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Blake Hernandez @loxstoplox.bsky.social · May 28

Thank you Madhura!

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Blake Hernandez @loxstoplox.bsky.social · May 27

Thank you so much Sam!

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Reposted by Blake Hernandez

Andy Moore @aaandmoore.bsky.social · May 25

Actin sun.

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Blake Hernandez @loxstoplox.bsky.social · May 24

🤣🤣🤣🤣

Blake Hernandez @loxstoplox.bsky.social · May 24

Thank you so much Pablo!

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Blake Hernandez @loxstoplox.bsky.social · May 24

You appear to suggest that nuclear actin filaments disassemble during interphase. However, using phalloidin labeling we observed that nuclear actin density increases over the course of cell cycle progression.

Blake Hernandez @loxstoplox.bsky.social · May 24

Hi Robert, I’m assuming this is in response to Manuel’s post. I’m very familiar with your paper, nice work! Again, I disagree that the conclusions in my paper are similar to yours. In fact, here’s an example from your paper where we reach very different conclusions.

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Blake Hernandez @loxstoplox.bsky.social · May 23

#FluorescenceFriday

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Blake Hernandez @loxstoplox.bsky.social · May 23

Paper link: www.science.org/doi/10.1126/...

Actin organizes chromosomes and microtubules to ensure mitotic fidelity in the preimplantation embryo

Following fertilization, the preimplantation embryo undergoes successive rounds of cell division and must accurately propagate the genetic material to ensure successful development. However, early mam...

www.science.org

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Blake Hernandez @loxstoplox.bsky.social · May 23

A big thank you to our collaborators and the entire lab for their support inside and outside of lab! And huge shoutout to UPenn alum and actin guru @aaandmoore.bsky.social for key technical advice during the early stages of the project!!

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Blake Hernandez @loxstoplox.bsky.social · May 23

I won’t spoil the details of the entire paper here, but we also identified a network of branched actin at the metaphase spindle periphery that modulates spindle size, offering a new explanation for the spindle scaling behavior seen in large acentriolar cells.

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Blake Hernandez @loxstoplox.bsky.social · May 23

Surprisingly, network contraction is not driven by myosin-2. We instead found that contractile stress is generated by filament disassembly within the crosslinked network. We propose that after nebd, formin dilution from the nuclear region triggers filament disassembly and network contraction.

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Blake Hernandez @loxstoplox.bsky.social · May 23

Actin to the rescue! A network of nuclear actin cables captures prophase chromosomes and contracts following nuclear envelope breakdown, gathering chromosomes towards the cell center. We propose that this mechanism of chromosome organization is required to achieve mitotic fidelity.

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Blake Hernandez @loxstoplox.bsky.social · May 23

Even more puzzling, the first phase of mitotic chromosome organization occurs independently of spindle microtubules. So then what cellular component generates the necessary force to organize chromosomes?

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Blake Hernandez @loxstoplox.bsky.social · May 23

It’s therefore puzzling that spindle assembly in the early embryo is highly inefficient, exemplified by comically disordered spindles during early mitosis (shown below).

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Blake Hernandez @loxstoplox.bsky.social · May 23

In the classical view of mitotic cell division, the spindle apparatus maintains principal control of chromosome capture and alignment. Any breakdown in spindle function can result in chromosome mis-segregation, producing daughter cells with abnormal chromosome number.

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Blake Hernandez @loxstoplox.bsky.social · May 23

I’m excited to announce that my paper describing non-canonical mitotic mechanisms in the early mouse embryo is out in @science.org ! (link at end of 🧵)

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Blake Hernandez @loxstoplox.bsky.social · May 23

The first part of the paper is indeed closely aligned with great work from the Lenart lab. It’s also important to note that our paper focuses on mitosis, whereas much of the work you referenced centers on meiosis.

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Blake Hernandez @loxstoplox.bsky.social · May 23

Regarding your comments on novelty: while it’s true that our work builds on the results of others (including your own), I disagree with the comparison to great work from the Schuh, Mogessie, or Grosse labs.

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Blake Hernandez @loxstoplox.bsky.social · May 23

Hi Manuel, big fan of your work! I’d like to point out that the manuscript you reviewed is not the version that was ultimately published. Once you’ve had a chance to read the final version, I’d really appreciate hearing your thoughts.

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Blake Hernandez @loxstoplox.bsky.social · May 23

Thank you Christophe!! I’ll post a thread later today

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Reposted by Blake Hernandez

Christophe 🔬 L @christlet.bsky.social · May 23

Actin does it again #cytoskeletonwar

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Blake Hernandez @loxstoplox.bsky.social · May 13

Quincy gets my vote for Off the Wall alone!

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