Abstract
Although the molecular mechanisms directing anteroposterior patterning of the Drosophila embryo (long-germband mode) are well understood, how these mechanisms were evolved from an ancestral mode of insect embryogenesis remains largely unknown. In order to gain insight into mechanisms of evolution in insect embryogenesis, we have examined the expression and function of the orthologue of Drosophila caudal (cad) in the intermediate-germband cricket Gryllus bimaculatus. We observed that a posterior (high) to anterior (low) gradient in the levels of Gryllus bimaculatus cad (Gb′ cad) transcript was formed in the early-stage embryo, and then Gb′ cad was expressed in the posterior growth zone until the posterior segmentation was completed. Reduction of Gb′ cad expression level by RNA interference resulted in deletion of the gnathum, thorax, and abdomen in embryos, remaining only anterior head. We found that the gnathal and thoracic segments are formed by Gb′ cad probably through the transcriptional regulation of gap genes including Gb′ hunchback and Gb′ Krüppel. Furthermore, Gb′ cad was found to be involved in the posterior elongation, acting as a downstream gene in the Wingless/Armadillo signalling pathways. These findings indicate that Gb′ cad does not function as it does in Drosophila, suggesting that regulatory and functional changes of cad occurred during insect evolution. Since Wnt/Cdx pathways are involved in the posterior patterning of vertebrates, such mechanisms may be conserved in animals that undergo sequential segmentation from the posterior growth zone.
| Original language | English |
|---|---|
| Pages (from-to) | 231-239 |
| Number of pages | 9 |
| Journal | Mechanisms of Development |
| Volume | 122 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Feb 2005 |
| Externally published | Yes |
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Keywords
- Anteroposterior patterning
- caudal
- Gryllus bimaculatus
- Intermediate-germband insect
- RNA interference
- Segmentation
- Wingless/Armadillo signalling
ASJC Scopus subject areas
- Developmental Biology
- Developmental Neuroscience
Cite this
caudal is required for gnathal and thoracic patterning and for posterior elongation in the intermediate-germband cricket Gryllus bimaculatus. / Shinmyo, Yohei; Mito, Taro; Matsushita, Takashi; Sarashina, Isao; Miyawaki, Katsuyuki; Ohuchi, Hideyo; Noji, Sumihare.
In: Mechanisms of Development, Vol. 122, No. 2, 02.2005, p. 231-239.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - caudal is required for gnathal and thoracic patterning and for posterior elongation in the intermediate-germband cricket Gryllus bimaculatus
AU - Shinmyo, Yohei
AU - Mito, Taro
AU - Matsushita, Takashi
AU - Sarashina, Isao
AU - Miyawaki, Katsuyuki
AU - Ohuchi, Hideyo
AU - Noji, Sumihare
PY - 2005/2
Y1 - 2005/2
N2 - Although the molecular mechanisms directing anteroposterior patterning of the Drosophila embryo (long-germband mode) are well understood, how these mechanisms were evolved from an ancestral mode of insect embryogenesis remains largely unknown. In order to gain insight into mechanisms of evolution in insect embryogenesis, we have examined the expression and function of the orthologue of Drosophila caudal (cad) in the intermediate-germband cricket Gryllus bimaculatus. We observed that a posterior (high) to anterior (low) gradient in the levels of Gryllus bimaculatus cad (Gb′ cad) transcript was formed in the early-stage embryo, and then Gb′ cad was expressed in the posterior growth zone until the posterior segmentation was completed. Reduction of Gb′ cad expression level by RNA interference resulted in deletion of the gnathum, thorax, and abdomen in embryos, remaining only anterior head. We found that the gnathal and thoracic segments are formed by Gb′ cad probably through the transcriptional regulation of gap genes including Gb′ hunchback and Gb′ Krüppel. Furthermore, Gb′ cad was found to be involved in the posterior elongation, acting as a downstream gene in the Wingless/Armadillo signalling pathways. These findings indicate that Gb′ cad does not function as it does in Drosophila, suggesting that regulatory and functional changes of cad occurred during insect evolution. Since Wnt/Cdx pathways are involved in the posterior patterning of vertebrates, such mechanisms may be conserved in animals that undergo sequential segmentation from the posterior growth zone.
AB - Although the molecular mechanisms directing anteroposterior patterning of the Drosophila embryo (long-germband mode) are well understood, how these mechanisms were evolved from an ancestral mode of insect embryogenesis remains largely unknown. In order to gain insight into mechanisms of evolution in insect embryogenesis, we have examined the expression and function of the orthologue of Drosophila caudal (cad) in the intermediate-germband cricket Gryllus bimaculatus. We observed that a posterior (high) to anterior (low) gradient in the levels of Gryllus bimaculatus cad (Gb′ cad) transcript was formed in the early-stage embryo, and then Gb′ cad was expressed in the posterior growth zone until the posterior segmentation was completed. Reduction of Gb′ cad expression level by RNA interference resulted in deletion of the gnathum, thorax, and abdomen in embryos, remaining only anterior head. We found that the gnathal and thoracic segments are formed by Gb′ cad probably through the transcriptional regulation of gap genes including Gb′ hunchback and Gb′ Krüppel. Furthermore, Gb′ cad was found to be involved in the posterior elongation, acting as a downstream gene in the Wingless/Armadillo signalling pathways. These findings indicate that Gb′ cad does not function as it does in Drosophila, suggesting that regulatory and functional changes of cad occurred during insect evolution. Since Wnt/Cdx pathways are involved in the posterior patterning of vertebrates, such mechanisms may be conserved in animals that undergo sequential segmentation from the posterior growth zone.
KW - Anteroposterior patterning
KW - caudal
KW - Gryllus bimaculatus
KW - Intermediate-germband insect
KW - RNA interference
KW - Segmentation
KW - Wingless/Armadillo signalling
UR - http://www.scopus.com/inward/record.url?scp=12344285129&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=12344285129&partnerID=8YFLogxK
U2 - 10.1016/j.mod.2004.10.001
DO - 10.1016/j.mod.2004.10.001
M3 - Article
C2 - 15652710
AN - SCOPUS:12344285129
VL - 122
SP - 231
EP - 239
JO - Mechanisms of Development
JF - Mechanisms of Development
SN - 0925-4773
IS - 2
ER -