Rough draft.This research track is under review with Dr. Atit's lab. Content and sequence may still change.
The Baby Mateo Case
Developmental domainPrinciples of Biomedical Science (PBS)Lesson 13 of 20Your seat: Cell biologist (epithelial team, genetics overlap)
Periderm and IRF6, the Non-Stick Coating on the Embryo
Discovery question
What keeps the surfaces inside the mouth from sticking to the wrong neighbor, and what happens when that protection is missing?
💡 The is a one-cell-thick non-stick coating built by IRF6; without it the oral surfaces glue to the wrong neighbors and block the shelves from lifting.
The plan
Prerequisite check
Before this page, you should know
- A single cranial cell can become bone (), skin (dermal fibroblast), or (chondrocyte), choosing at about mouse day E11.5.
- is the : the fate the cell takes when nothing tells it otherwise.
Today's new idea is only
The is a one-cell-thick non-stick coating built by IRF6; without it the oral surfaces glue to the wrong neighbors and block the shelves from lifting.
Learn first
What you will learn
Goal: Explain that the is a non-stick protective layer made by the gene IRF6, and that losing it lets oral surfaces glue to the wrong neighbors and block .
Know by the end
- The is a single flat layer of cells that wraps embryonic skin and mouth lining and acts as a controlled non-stick coating.
- At true sites the peels away on cue so the layers underneath can join; elsewhere it keeps wrong surfaces apart.
- IRF6 is the gene that builds a working and is the strongest known gene in humans.
- When IRF6 is lost the oral surfaces become sticky, form intraoral adhesions, and physically block the shelves from elevating, giving .
Learn first
Model: Delete the coating gene, watch the wrong things stick (mouse and zebrafish data)
Scientists found the gene that builds a working : IRF6.
With IRF6 working (normal), the forms a non-stick layer, surfaces only join where they should, and the elevates and fuses. With IRF6 broken or deleted in the mouse, the periderm fails to differentiate, oral surfaces become sticky and form abnormal intraoral adhesions (palate stuck to tongue, upper jaw stuck to lower), and those glued surfaces physically block the palate shelves from lifting, giving palate (PMID:26589921). In zebrafish, a form makes periderm cells lose their hold and the literally ruptures at the surface, dramatic visual proof that the periderm is a real barrier (PMID:26692521).
Do the work
Explore (work the model before reading on)
- What is the , and how many cell layers thick is it?
- When IRF6 was deleted in the mouse, what stuck to what, and what step did that block?
- The has to do two opposite-sounding jobs: keep some surfaces apart AND let other surfaces join. How can one coating do both?
- When IRF6 is broken the shelves cannot even lift into place. So is IRF6 a -only gene, or does it matter at an earlier step too? Use the evidence.
- Predict what you would see if a baby had a weak version of IRF6 that made a slightly too-sticky . Would you expect a clean , or surfaces that catch on the wrong neighbors?
The plan
Guided notes
1
A coating with two jobs
Model start: The is a single, flat layer of cells that wraps the outside of embryonic skin and the lining of the mouth.
- It works as a ____ (non-stick) coating: it stops surfaces from gluing to the wrong neighbor.
- At true sites it ____ (peels away / desquamates) so the layers underneath can join.
2
What IRF6 loss does
- When IRF6 is lost, the does not differentiate and the oral surfaces form abnormal ____ (intraoral adhesions).
- Those stuck surfaces physically block the shelves from ____ (elevating / lifting), so the palate cannot fuse.
- IRF6 also acts ____ (cell-autonomously) in bone, so mice without it show poor craniofacial bone and a small jaw.
Explore
Reading the Research
What to read
Read the title and the abstract only, not the whole paper. Lan & Jiang 2015, Cellular and Molecular Mechanisms of Palatogenesis (Curr Top Dev Biol)
Why this source matters
This is the published evidence behind today's idea: The is a one-cell-thick non-stick coating built by IRF6; without it the oral surfaces glue to the wrong neighbors and block the shelves from lifting.
Words to unlock first
Reading moves
- Skim the title and abstract first to get the gist.
- Circle the one sentence that states the main claim.
- Box the evidence the authors give for that claim.
- Mark one sentence that confuses you, and move on.
Stop point
You do not need the methods or statistics yet. If a sentence is about lab technique or math you have not learned, mark it and skip it.
Your output
Write one claim-evidence sentence: what this source claims, and the one piece of evidence that backs it up.
Where this fits
Tested on (Ohio WebXam)
Genetics of Disease · 072130
PLTW lesson
MI · Developmental domain · PLTW PBS 072110
WebXam domain
Bio-Molecular Technology
Evidence to produce
Annotate a diagram of a palate shelf rising next to the tongue. Label two arrows: one to a surface that must NOT stick (shelf to tongue) and one to a surface that MUST fuse (shelf edge to shelf edge). Finish: "The periderm and its gene IRF6 matter because they decide ____," then add one line on why a sticky periderm could cause a cleft even though no shelf failed to grow.
Lab / skill
Principles of Biomedical Science (PBS)
Explore
Vetted readings for this lesson
- Lan & Jiang 2015, Cellular and Molecular Mechanisms of Palatogenesis (Curr Top Dev Biol)
- Liu et al. 2016, Irf6 directly regulates Klf17 in zebrafish periderm and Klf4 in murine oral epithelium (journal link; use class excerpt if blocked)
- Thompson et al. 2019, A Cleft Lip and Palate Gene, Irf6, in Osteoblast Differentiation of Craniofacial Bone (journal link; use class excerpt if blocked)
The plan
Track your progress today
Check these off as you work through the lesson, then submit. This tells Mr. Mendoza how you're doing so he can help the class. It does not replace turning in your producible.
Use the code Mr. Mendoza gave you, not your name. Saved on this device.
Check off as you finish
- Read the Model and answered the Explore questions.
- Filled in the guided notes in my own words.
- Defined the new vocabulary with an example.
- Built the producible: Annotate a diagram of a palate shelf rising next to the tongue. Label two arrows: one to a surface that must NOT stick (shelf to tongue) and one to a surface that MUST fuse (shelf edge to shelf edge). Finish: "The periderm and its gene IRF6 matter because they decide ____," then add one line on why a sticky periderm could cause a cleft even though no shelf failed to grow.
- Wrote my Claim, Evidence, and Reasoning exit ticket.
Pick your period and code first.
Check yourself
Exit ticket (Claim, Evidence, Reasoning)
- Claim: The is a non-stick coating, and IRF6 is the gene that builds it.
- Evidence: When IRF6 was deleted, the oral surfaces became ____ and formed abnormal ____, which blocked the shelves from ____.
- Reasoning: If losing IRF6 makes the wrong surfaces stick, then IRF6's normal job must be to ____.
How this is graded (rubric)
For: Annotate a diagram of a palate shelf rising next to the tongue. Label two arrows: one to a surface that must NOT stick (shelf to tongue) and one to a surface that MUST fuse (shelf edge to shelf edge). Finish: "The periderm and its gene IRF6 matter because they decide ____," then add one line on why a sticky periderm could cause a cleft even though no shelf failed to grow.
| Criterion | Proficient | Developing | Beginning |
|---|---|---|---|
| Complete | Every required part of the artifact is present and filled in. | Most parts are present, but one is missing or left blank. | Several parts are missing. |
| Accurate | The science and data are correct and match the evidence. | Mostly correct, with a small factual slip. | Key science or data is wrong. |
| Scientific reasoning (CER) | States a claim, backs it with specific evidence, and explains the reasoning. | Has a claim and evidence, but the reasoning is thin or missing. | Gives an answer with no evidence or reasoning. |
| Professional communication | Clear, organized, and labeled the way a clinician or scientist would write it. | Readable but disorganized or missing labels. | Hard to follow. |
| Submitted | Turned in the right way (Schoology for routine work) and confirmed. | Turned in, but in the wrong place or unconfirmed. | Not turned in. |
How the model answer scores against this rubric
- CompleteProficient: Nothing is left blank: the model fills every part of "Annotate a diagram of a palate shelf rising next to the tongue. Label two arrows: one to a surface that must NOT stick (shelf to tongue) and one to a surface that MUST fuse (shelf edge to shelf edge). Finish: "The periderm and its gene IRF6 matter because they decide ____," then add one line on why a sticky periderm could cause a cleft even though no shelf failed to grow.".
- AccurateProficient: Every number and claim matches the case evidence.
- Scientific reasoning (CER)Proficient: It names a claim, cites the specific evidence, and explains the reasoning, not just the answer.
- Professional communicationProficient: It is organized and labeled like a real chart note.
- SubmittedProficient: It would be turned in on Schoology and confirmed.
Explore
Where this leads: careers
Cell biologist Geneticist
What's next: We now know which surfaces must stay apart and which must fuse, and which gene polices that. But clefts come in different forms: some only the lip, some only the , some both. Which exact step fails for a lip versus a cleft palate?
The Wnt/beta-catenin Master Switch, How a Face Cell Decides What NOT to BeMapping the Failure, Which Step Breaks for a Cleft Lip Versus a Cleft Palate