Hoxb6 can interfere with the segmentation program

The group of Moises Mallo at the Instituto Gulbenkian de Ciência published in Development. The authors show that forced expression of Hoxb6 in the paraxial mesoderm produces non-rib-related malformations due to problems in somitogenesis and anterior-posterior somite patterning, which result from dysregulated expression of the oscillator gene Lfng. Dysregulated Lfng expression was restricted to regions posterior to the hindlimb, suggesting that the mechanisms of paraxial segmentation are not uniform along the main body axis as previously thought. These data provide a mechanistic connection between Hoxb6 expression and the mammalian segmentation clock and convincingly demonstrate functional differences in somitogenesis before and after the trunk-to-tail transition. The authors postulate that their data suggest the existence of yet-to-be-identified differential mechanisms operating during development of the trunk or tail areas of the body axis. See article here.