Mcrs1 interacts with Six1 to influence early craniofacial and otic development

Area of Science:

• Developmental Biology
• Genetics
• Molecular Biology

Background:

• Six1 transcription factor is vital for craniofacial development.
• Mutations in SIX1 and EYA1 cause Branchio-otic/Branchio-oto-renal syndrome (BOR), a disorder with craniofacial, otic, and renal malformations.
• Identifying interacting proteins of Six1 can reveal novel genes involved in BOR.

Purpose of the Study:

• To characterize the developmental role of Microspherule protein 1 (Mcrs1).
• To investigate the interaction between Mcrs1 and Six1 in craniofacial development.
• To understand Mcrs1's role in Branchio-otic/Branchio-oto-renal syndrome.

Main Methods:

• In vitro binding assays to assess Mcrs1 and Six1 interaction.
• Reporter assays to measure Six1-Eya1 transcriptional activation.
• In vivo knock-down and overexpression studies in embryonic models.
• Analysis of gene expression patterns for neural plate, neural crest, and cranial placode markers.
• Assessment of otic vesicle development and gene expression.

Main Results:

• Mcrs1 binds to Six1 and inhibits Six1-Eya1 transcriptional activity in cultured cells.
• Mcrs1 knock-down in embryos alters expression of neural plate, neural crest, and cranial placode genes.
• Loss of Mcrs1 leads to reduced otic vesicle gene expression and smaller otic vesicle volume.
• Overexpression of Mcrs1 favors neural crest gene expansion over cranial placode genes and reduces otic vesicle gene expression.

Conclusions:

• Mcrs1 functionally interacts with Six1 during embryonic development.
• This Mcrs1-Six1 interaction is critical for craniofacial development, particularly for otic vesicle formation.
• Understanding this interaction provides insights into the pathogenesis of Branchio-otic/Branchio-oto-renal syndrome.