It is well established that TH activates new patterns of gene expression during anuran metamorphosis and vertebrate brain development (Shi 2000), including changes in cellular metabolism not unlike the highly enriched mitochondrial biological processes that we observed in our study.
During metamorphosis, larval epidermal tissues undergo cellular restructuring and rearrangement to give rise to adult abdominal epithelium.
This makes the silkworm a good model for studying insect development and metamorphosis, which are processes that include cellular proliferation, tissue remodeling, cell migration, and programmed cell death [25] [26].
The detected age-related changes in expression of categories involved in metamorphosis including imaginal disc development and cellular morphogenesis are more difficult to interpret in the context of ageing.
The Xenopus laevis larval-to-adult intestinal remodeling during metamorphosis has been well characterized at both the cellular and molecular levels [ 8].
Thus, rising TH levels during larval development bring about metamorphosis by triggering transcriptional programs that activate tissue remodeling, cellular differentiation, and tissue regression developmental processes that transform larval phenotypes into adult phenotypes (Shi 2000).
This is compatible with the idea that some genes required for tissue reconstruction during metamorphosis are also recruited for the response against RasV12-induced cellular changes.
These data suggest that in the absence of Dnhe2, pHi homeostasis during metamorphosis can be maintained by alternative ion transport mechanisms, changes in cellular buffering capacity and/or metabolic changes.
Their future importance in regenerative biology and metamorphosis will almost certainly escalate as genome resources and other molecular and cellular approaches become widely available.
This has enabled cellular, molecular, and genetic analyses on the formation of the adult intestinal stem cells during intestinal metamorphosis [ 1, 16– 16].
