title: A segmentation clock with two-segment periodicity in insects.
abstract: Vertebrate segmentation relies on a mechanism characterized by oscillating gene expression. Whether this mechanism is used by other segmented animals has been controversial. Rigorous proof of cyclic expression during arthropod segmentation has been lacking. We find that the segmentation gene odd-skipped (Tc-odd) oscillates with a two-segment periodicity in the beetle Tribolium castaneum. By bisecting embryos and culturing the two halves over different time intervals, we demonstrate that Tc-odd cycles with a period of about 95 minutes at 30°C. Using live imaging and cell tracking in green fluorescent protein-expressing embryos, we can exclude that cell movements explain this dynamic expression. Our results show that molecular oscillators represent a common feature of segmentation in divergent animals and help reconcile the contrasting paradigms of insect and vertebrate segmentation.
authors.affiliation: Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Nikolaou Plastira 100, GR-70013 Heraklio, Crete, Greece.
authors.forename: Andres F
authors.initials: AF
authors.lastname: Sarrazin
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Peel
authors.forename: Michalis
authors.initials: M
authors.lastname: Averof
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D019521:Body Patterning / Q000235:genetics; D002465:Cell Movement; D004625:Embryo, Nonmammalian / Q000502:physiology; D047108:Embryonic Development; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D010507:Periodicity; D046509:Tissue Culture Techniques; D014231:Tribolium / Q000166:cytology / Q000196:embryology* / Q000235:genetics*