DECK 3: Case Study 1 - Pierre Robin Sequence (PRS) - Detailed Template

memorise the complete PRS story in a logical sequence. You must be able to tell this story from gene to phenotype to technique to mechanism.

What gene is affected in PRS?

SOX9

What is the inheritance pattern of PRS?

Autosomal dominant

What are the primary phenotypic features?

Craniofacial abnormalities, cleft palate

What developmental process is disrupted?

Neural crest differentiation

How far from SOX9 are the regulatory elements?

1 Mb away (upstream and downstream)

What are the three enhancer loci identified near SOX9?

EC1.45, EC1.35, EC1.25

Which enhancer alone cannot drive craniofacial expression?

EC1.35

What assay showed these regions drive craniofacial expression?

LacZ reporter assay in developing mouse embryos

What chromatin capture method confirmed these as SOX9 enhancers?

Capture-C (SOX9 promoter as viewpoint)

What do the Capture-C data show?

Prominent loops between SOX9 promoter and EC1.45, EC1.35, EC1.25

What types of genetic variants cause PRS?

Deletions, translocations, SNVs

What transcription factor binding motif is disrupted by SNVs?

TWIST

What happens when TWIST binding is disrupted?

Abrogates typical neural crest differentiation

What histone marks mark these SOX9 enhancers?

H3K27ac, P300 binding (active enhancers)

What did the Wysocka lab map to identify these enhancers?

P300, H3K27ac, chromatin accessibility