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Background: Cilia are important for Hedgehog signaling in vertebrates and many genes that encode proteins involved in ciliogenesis have been studied for their roles in embryonic development. Null mutations in many of these genes cause early embryonic lethality, hence an understanding of their roles in postnatal development is limited. Results: The Inturned (Intu) gene is required for ciliogenesis and here we report a recessive hypomorphic mutation, resulting in substitution of a conserved hydrophobic residue (I813N) near the C-terminus, that sheds light on later functions of Intu. Mice homozygous for this Double-thumb (IntuDtm) allele exhibit polydactyly, retarded growth, and reduced survival. There is a moderate loss of cilia in IntuDtm/Dtm mutants, and IntuI813N exhibits compromised ability to increase ciliogenesis in cultured Intu null mutant cells. IntuDtm mutants show rib defects and delay of endochondral ossification in long bones, digits, vertebrae, and the sternum. These skeletal defects correlate with a decrease in Hh signaling. However, patterning of the neural tube and planar cell polarity appear to be normal. Conclusions: This hypomorphic Intu allele highlights an important role of Intu in mouse skeletal development. Developmental Dynamics 244:736–747, 2015. © 2015 Wiley Periodicals, Inc.

Background: Lung-branching morphogenesis is a fundamental developmental process, yet the cellular dynamics that occur during lung development and the molecular mechanisms underlying recent postulated branching modes are poorly understood. Results: Here, we implemented a time-lapse video microscopy method to study the cellular behavior and molecular mechanisms of planar bifurcation and domain branching in lung explant- and organotypic cultures. Our analysis revealed morphologically distinct stages that are shaped at least in part by a combination of localized and orientated cell divisions and by local mechanical forces. We also identified myosin light-chain kinase as an important regulator of bud bifurcation, but not domain branching in lung explants. Conclusions: This live imaging approach provides a method to study cellular behavior during lung-branching morphogenesis and suggests the importance of a mechanism primarily based on oriented cell proliferation and mechanical forces in forming and shaping the developing lung airways. Developmental Dynamics 242:622–637, 2013. © 2013 Wiley Periodicals, Inc.

There are approximately 4,800 extant species of mammals that exhibit tremendous morphological, physiological, and developmental diversity. Yet embryonic development has been studied in only a few mammalian species. Among mammals, bats are second only to rodents with regard to species number and habitat range and are the most abundant mammals in undisturbed tropical regions. Bat development, though, remains relatively unstudied. Here, we describe and illustrate a staging series of embryonic development for the short-tailed fruit bat, Carollia perspicillata, based on embryos collected at timed intervals after captive matings. As Carollia can be readily maintained and propagated in captivity and is extremely abundant in the wild, it offers an attractive choice as a chiropteran model organism. This staging system provides a framework for studying Carollia embryogenesis and should prove useful as a guide for embryological studies of other bat species and for comparisons with other orders of mammals.