2025-03-04 基礎生物学研究所
<関連情報>
- https://www.nibb.ac.jp/pressroom/news/2025/03/04.html
- https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/dvdy.763
- https://onlinelibrary.wiley.com/doi/10.1111/dgd.12958
- https://onlinelibrary.wiley.com/doi/10.1111/dgd.12952
ウロデレ両生類イモリが膵臓の進化発生におけるミッシングリンクに架け橋をかける Urodele amphibian newt bridges the missing link in evo-devo of the pancreas
Ryosuke Morozumi, Kazuko Okamoto, Eriko Enomoto, Yuta Tsukamoto, Mitsuki Kyakuno, Nanoka Suzuki, Ichiro Tazawa, Nobuaki Furuno, Hajime Ogino, Yasuhiro Kamei, Masatoshi Matsunami …
Developmental Dynamics Published: 08 January 2025
DOI:https://doi.org/10.1002/dvdy.763
Abstract
Background
The pancreas exhibits diverse structures and roles across vertebrates. The pancreas has evolved to include both endocrine and exocrine cells, a change that occurred during the transition from fish to amphibian. This event emphasizes the evolutionary significance of amphibians. However, research has focused predominantly on anuran amphibians, with urodeles, such as newts, remaining underexplored. In this study, we investigated the development of the pancreas using Pleurodeles waltl as a model species of urodele.
Results
The newt pancreas consists of a single organ with exocrine tissue characterized by acinar structures and endocrine tissue forming islets. Notably, the newt possesses unique pancreas-like tissues on their intestines. We found that disruption of the newt Pancreatic and Duodenal Homeobox (Pdx) 1 gene resulted in an underdeveloped pancreas. Conversely, disruption of the Pdx2 paralog in newt had no significant impact on pancreatic development.
Conclusion
The newt pancreas shows a morphology similar to that of the mammalian pancreas, which includes both exocrine and endocrine tissues. These results highlight the intermediate evolutionary position of the newt in the context of the evolution of pancreatic development.
Our findings indicate that characterization of the newt pancreas will be crucial for understanding the evolutionary progression of pancreatic function in vertebrates.
Cdk1遺伝子破壊がイモリ細胞の細胞周期進行に及ぼす影響 Effect of Cdk1 gene disruption on cell cycle progression in newt cells
Yuta Nakao, Kazuko Okamoto, Ichiro Tazawa, Tatsuro Nishijima, Nobuaki Furuno, Tetsushi Sakuma, Takashi Yamamoto, Takashi Takeuchi, Toshinori Hayashi
Development, Growth & Differentiation Published: 08 January 2025
DOI:https://doi.org/10.1111/dgd.12958
Abstract
Cyclin-dependent kinases (CDKs) are key regulators of cell cycle progression, in conjunction with cyclins. The cyclin-CDK system is highly conserved among eukaryotes, and CDK1 is considered essential for progression through the M phase. However, the extent to which cell cycle progression depends on CDK1 varies between cell types. Therefore, a range of cell types must be analyzed to comprehensively elucidate the role of CDK1. Cdk1-knockout mice exhibit lethality at an early developmental stage, specifically before the differentiation of various cell types. The aim of the present study was to characterize the effects of CDK1 deficiency in amphibian newts. Cdk1 was disrupted by injecting fertilized newt eggs with CRISPR/Cas9, and the resulting effects on embryonic development and cell proliferation were then evaluated. In both wild-type and Cdk1-crispant newt embryos, CDK1 protein was either stored in the egg until late embryogenesis or potentially derived from maternal mRNA, which may also be stored during this period. The embryos survived to the hatching stage, during which the cells responsible for forming the basic organs differentiated. To further characterize the long-term effects of Cdk1 knockout, parabiosis experiments were conducted using wild-type embryos and Cdk1 crispants. The results suggested that an endocycle occurred in the crispant larvae, as evidenced by increases in the size of several types of cells. It is anticipated that studies using newts will provide further insights into the role of Cdk1 in regulating the cell cycle.
Fgf10やTbx4との相互作用を通じてイモリの後肢芽の成長を制御するHox13の新規機能 Novel function of Hox13 in regulating outgrowth of the newt hindlimb bud through interaction with Fgf10 and Tbx4
Sayo Tozawa, Haruka Matsubara, Fumina Minamitani, Yasuhiro Kamei, Misako Saida, Momoko Asao, Ken-ichi T. Suzuki, Masatoshi Matsunami, Shuji Shigenobu, Toshinori Hayashi …
Development, Growth & Differentiation Published: 26 December 2024
DOI:https://doi.org/10.1111/dgd.12952
Abstract
5′Hox genes regulate pattern formation along the axes of the limb. Previously, we showed that Hoxa13/Hoxd13 double-mutant newts lacked all digits of the forelimbs during development and regeneration, showing that newt Hox13 is necessary for digit formation in development and regeneration. In addition, we found another unique phenotype. Some of the Hox13 crispant newts showed hindlimb defects, in which whole or almost whole hindlimbs were lost, suggesting a novel function of Hox13 in limb development. Using germline mutants, we showed that mutation in Hox13 led to hindlimb defects. The limb buds of Hox13 crispants formed, however, did not show outgrowth. Expression of Fgf10 and Tbx4, which are involved in limb outgrowth, decreased in the hindlimb buds of Hox13 crispants. In addition, hindlimb defects were observed in both Fgf10 and Tbx4 crispant newts. Finally, Fgf10 and Tbx4 interacted with Hox13 genetically. Our results revealed a novel function of Hox13 in regulating the outgrowth of the newt hindlimb bud through interaction with Fgf10 and Tbx4.
