Brachyenteron is necessary for morphogenesis of theposterior gut but not for anteroposterior axial elongationfrom the posterior growth zone in the intermediate-germbandcricket Gryllus bimaculatus

Yohei Shinmyo, Taro Mito, Tomohiro Uda, Taro Nakamura, Katsuyuki Miyawaki, Hideyo Ohuchi, Sumihare Noji

Research output: Contribution to journalArticle

20 Citations (Scopus)


In the long-germband insect Drosophila, all body segments and posterior terminal structures, including the posterior gut and anal pads, are specified at the blastoderm stage. In short- and intermediate-germband insects, however, posterior segments are sequentially produced from the posterior growth zone, a process resembling somitogenesis in vertebrates, and invagination of the posterior gut starts after anteroposterior (AP) axial elongation from the growth zone. The mechanisms underlying posterior segmentation and terminal patterning in these insects are poorly understood. In order to elucidate these mechanisms, we have investigated the roles of the Brachyurylbrachyenteron (Bra/byn) homolog in the intermediate-germ band cricket Gryllus bimaculatus. Loss-of-function analysis by RNA interference (RNAi) revealed that Gryllus byn (Gb'byn) is not required for AP axial elongation or normal segment formation, but is required for specification of the posterior gut. We also analyzed Gryllus caudal (Gb'cad) RNAi embryos using in situ hybridization with a Gb'byn probe, and found that Gb'cad is required for internalization of the posterior gut primordium, in addition to AP axial elongation. These results suggest that the functions of byn and cad in posterior terminal patterning are highly conserved in Gryllus and Drosophila despite their divergent posterior patterning. Moreover, because it is thought that the progressive growth of the AP axis from the growth zone, controlled by a genetic program involving Cdx/cad and Bra/byn, might be ancestral to bilaterians, our data suggest that the function of Bra/byn in this process might have been lost in insects.

Original languageEnglish
Pages (from-to)4539-4547
Number of pages9
Issue number22
Publication statusPublished - Nov 1 2006
Externally publishedYes



  • Brachyenteron
  • Caudal
  • Gryllus bimaculatus
  • Intermediate-germband insect
  • Posterior patterning
  • RNA interference

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology

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