Oliveira Lab

Chromosome Dynamics Lab @ Católica Biomedical Research. Aiming to understand how mitotic chromosomes are assembled and influence mitotic fidelity

[Oliveira Lab @CHR_lab]

🧵1/
Excited to share our new preprint!
We uncover a new layer of control in how cells restart transcription after mitosis.
👉 TTF2 prevents premature rRNA transcription during mitotic exit (https://t.co/LgfirEoKEw)

[Oliveira Lab @CHR_lab]

@Mech_Morph_Lab Many thanks, Elias @Mech_Morph_Lab

[Oliveira Lab @CHR_lab]

🧵1/
Excited to share our new preprint!
We uncover a new layer of control in how cells restart transcription after mitosis.
👉 TTF2 prevents premature rRNA transcription during mitotic exit (https://t.co/LgfirEoKEw)

[Oliveira Lab @CHR_lab]

12/ Huge congratulations to the great team: @catarinaapedro @MicrodotLaura @peneda_catarina and Mia.

[Oliveira Lab @CHR_lab]

12/
Preprint here 👇
(https://t.co/LgfirEoKEw)
Would love feedback!

[Oliveira Lab @CHR_lab]

10/
Our work links two fields that often don’t talk enough:
🧬 Mitosis
🧬Transcription regulation
and highlights how their coordination preserves cellular integrity

[Oliveira Lab @CHR_lab]

9/
We further show that:
Disrupting this timing → nucleolar fragmentation in interphase
👉 Mitotic transcription timing has consequences beyond mitosis

[Oliveira Lab @CHR_lab]

8/
Importantly, this challenges the idea that transcription simply resumes passively as cells exit mitosis.
Instead, reactivation is actively restrained and timed

[Oliveira Lab @CHR_lab]

7/
This leads to:
• early rRNA synthesis
• premature recruitment of nucleolar components
👉Transcription turns ON too early

[Oliveira Lab @CHR_lab]

6/
But here’s the unexpected part 👇
Loss of TTF2 triggers premature RNA Polymerase I activation during anaphase

[Oliveira Lab @CHR_lab]

5/
As expected:
Loss of TTF2 → retention of chromatin-associated transcripts in metaphase
(mainly RNA Pol II–derived)
✔️ Consistent with its known role in transcriptional clearance

[Oliveira Lab @CHR_lab]

4/
Using nascent RNA labeling + polymerase-specific perturbations,
we tracked transcription dynamics across mitosis in:
• human embryonic stem cells
• HeLa cells

[Oliveira Lab @CHR_lab]

3/
We focused on TTF2, a factor known to remove RNA Polymerase II transcripts at mitotic entry.
But what happens later—during transcriptional reactivation?

[Oliveira Lab @CHR_lab]

2/
During mitosis, transcription is globally shut down.
As cells exit mitosis, transcription must be reactivated—precisely and in the right order.
How this timing is controlled remains poorly understood.

[Barriga Lab @Mech_Morph_Lab]

We are #hiring ! Our lab is looking for a LabTech/Lab Manager! Take a look to our research here!
https://t.co/2WqLGjTjJ8

Drop a line if you are interested to know more details and please share!

#labtech #biology #JobAlert #labmanager #labwork #Xenopus #zebrafish #devbiol #Science

[Oliveira Lab @CHR_lab]

6/ 🧬 Check out the full preprint: https://t.co/F0wsdc6Djh

[Oliveira Lab @CHR_lab]

🧵 Thread: What happens when transcription isn’t properly shut off during mitosis? Our new preprint explores just that 👇
https://t.co/F0wsdc6Djh

[Oliveira Lab @CHR_lab]

5/ This means that mitotic transcription isn’t just a passive consequence of cell cycle stage — it actively threatens genome stability when not properly regulated.

[Oliveira Lab @CHR_lab]

4/ The result? When transcription isn’t cleared, sister chromatid resolution is impaired — a critical step needed to ensure faithful chromosome segregation in anaphase.

[Oliveira Lab @CHR_lab]

3/ Importantly, we show that these defects arise because R-loops form when transcription persists during mitosis — and preventing transcription reverts the defects. That establishes a causal link.

[Oliveira Lab @CHR_lab]

2/ Using TTF2 depletion to force nascent transcripts to persist on mitotic chromatin, we found that this abnormal retention leads to mitotic errors including abnormal chromosomes and bridges.

[Oliveira Lab @CHR_lab]

1/ During mitosis, cells globally suppress transcription as chromosomes condense — a conserved hallmark of cell division. But what if this repression fails? 😮‍💨