Ephrin receptors are the most common tyrosine kinase effectors operating during development. Ephrin receptor genes are reported to be up-regulated in the regenerating tail of the Podarcis muralis lizard. Thus, in the ...Ephrin receptors are the most common tyrosine kinase effectors operating during development. Ephrin receptor genes are reported to be up-regulated in the regenerating tail of the Podarcis muralis lizard. Thus, in the current study, we investigated immunolocalization of ephrin receptors in the Podarcis muralis tail during regeneration. Weak immunolabelled bands for ephrin receptors were detected at 15–17 kDa, with a stronger band also detected at 60–65 kDa. Labelled cells and nuclei were seen in the basal layer of the apical wound epidermis and ependyma, two key tissues stimulating tail regeneration. Strong nuclear and cytoplasmic labelling were present in the segmental muscles of the regenerating tail, sparse blood vessels, and perichondrium of regenerating cartilage. The immunolocalization of ephrin receptors in muscle that gives rise to large portions of new tail tissue was correlated with their segmentation. This study suggests that the high localization of ephrin receptors in differentiating epidermis, ependyma, muscle, and cartilaginous cells is connected to the regulation of cell proliferation through the activation of programs for cell differentiation in the proximal regions of the regenerating tail. The lower immunolabelling of ephrin receptors in the apical blastema, where signaling proteins stimulating cell proliferation are instead present, helps maintain the continuous growth of this region.展开更多
To understand the mechanisms of starfish regeneration, the arms of adult starfish Asterias rollestoni Bell were amputated and their regeneration patterns and cellular mechanisms were studied.It was found that cells in...To understand the mechanisms of starfish regeneration, the arms of adult starfish Asterias rollestoni Bell were amputated and their regeneration patterns and cellular mechanisms were studied.It was found that cells in the outer epidermis and inner parietal peritoneum near the end of the stump began to dedifferentiate 4 d after amputation. The dedifferentiated cells in the outer epidermis proliferated,migrated to the wound site and formed a thickened pre-epidermis which would then re-differentiate gradually into ma-ture epidermis.The new parietal peritoneum formed on the coelomic side of wound might be from the curvely elongated parietal peritoneum, resulting from the dedifferentiated and proliferated cells by extension. Afterwards, the proliferated cells made the outer epidermis and inner parietal peritoneum invaginate into the interior dermis and formed blastema-like structures together with induced dedifferentiated dermal cells. Most interestingly, the arm regeneration in A. rollestoni was achieved synchronously by de novo arm-bud formation and growth, and arm-stump elongation. The crucial aspects of arm-bud formation included cell dedifferentiation, proliferation and migration, while those of arm-stump elongation included cell dedifferentiation, proliferation, invagination, and arm-wall-across blastema-like structure formation. The unique pattern and cellular mechanisms of amputated arm regeneration make it easier to understand the rapid regeneration process of adult starfish. This study may lay solid foundations for the research into mo-lecular mechanisms of echinoderm regeneration.展开更多
基金mainly supported by the Comparative Histolab PadovaUniversity of Bologna
文摘Ephrin receptors are the most common tyrosine kinase effectors operating during development. Ephrin receptor genes are reported to be up-regulated in the regenerating tail of the Podarcis muralis lizard. Thus, in the current study, we investigated immunolocalization of ephrin receptors in the Podarcis muralis tail during regeneration. Weak immunolabelled bands for ephrin receptors were detected at 15–17 kDa, with a stronger band also detected at 60–65 kDa. Labelled cells and nuclei were seen in the basal layer of the apical wound epidermis and ependyma, two key tissues stimulating tail regeneration. Strong nuclear and cytoplasmic labelling were present in the segmental muscles of the regenerating tail, sparse blood vessels, and perichondrium of regenerating cartilage. The immunolocalization of ephrin receptors in muscle that gives rise to large portions of new tail tissue was correlated with their segmentation. This study suggests that the high localization of ephrin receptors in differentiating epidermis, ependyma, muscle, and cartilaginous cells is connected to the regulation of cell proliferation through the activation of programs for cell differentiation in the proximal regions of the regenerating tail. The lower immunolabelling of ephrin receptors in the apical blastema, where signaling proteins stimulating cell proliferation are instead present, helps maintain the continuous growth of this region.
基金supported by the funds for Natural Science Research from the Bureau of Science and Technology of Qingdao(04-2-JZ-8)
文摘To understand the mechanisms of starfish regeneration, the arms of adult starfish Asterias rollestoni Bell were amputated and their regeneration patterns and cellular mechanisms were studied.It was found that cells in the outer epidermis and inner parietal peritoneum near the end of the stump began to dedifferentiate 4 d after amputation. The dedifferentiated cells in the outer epidermis proliferated,migrated to the wound site and formed a thickened pre-epidermis which would then re-differentiate gradually into ma-ture epidermis.The new parietal peritoneum formed on the coelomic side of wound might be from the curvely elongated parietal peritoneum, resulting from the dedifferentiated and proliferated cells by extension. Afterwards, the proliferated cells made the outer epidermis and inner parietal peritoneum invaginate into the interior dermis and formed blastema-like structures together with induced dedifferentiated dermal cells. Most interestingly, the arm regeneration in A. rollestoni was achieved synchronously by de novo arm-bud formation and growth, and arm-stump elongation. The crucial aspects of arm-bud formation included cell dedifferentiation, proliferation and migration, while those of arm-stump elongation included cell dedifferentiation, proliferation, invagination, and arm-wall-across blastema-like structure formation. The unique pattern and cellular mechanisms of amputated arm regeneration make it easier to understand the rapid regeneration process of adult starfish. This study may lay solid foundations for the research into mo-lecular mechanisms of echinoderm regeneration.
