Frizzled6 controls hair patterning in mice

Area of Science:

• Developmental Biology
• Genetics
• Mammalian Development

Background:

• Macroscopic hair patterns, such as hair whorls, are observed in various mammalian species, including humans.
• The molecular mechanisms underlying the development of these patterns are not fully understood.

Purpose of the Study:

• To investigate the role of Frizzled6 (Fz6) in controlling macroscopic hair patterning in mice.
• To elucidate the cellular basis and evolutionary conservation of hair patterning mechanisms.

Main Methods:

• Targeted deletion of the Frizzled6 (Fz6) gene in mice.
• Analysis of hair patterns on the hind feet, head, and torso.
• Embryo chimera experiments to determine the site of Fz6 action.
• Comparison of Fz6-dependent patterning with Drosophila frizzled mutants.

Main Results:

• Frizzled6 (Fz6) gene deletion resulted in stereotyped hair whorls on hind feet, variable whorls and tufts on the head, and hair misorientation on the torso.
• Embryo chimera experiments indicated that Fz6 acts locally, with epithelial cells being the source of signaling.
• The observed hair patterning defects in mice resemble those seen in Drosophila frizzled mutants.

Conclusions:

• Frizzled6 (Fz6) is a key regulator of macroscopic hair patterning in mice.
• Mammalian hair patterning likely utilizes a Frizzled-dependent tissue polarity system conserved with Drosophila.
• This study provides insights into the genetic control and evolutionary origins of hair patterning.