Ozerova, A. M. | Search bioRxiv

bioRxiv2024

Temporal dynamics of gene expression during metamorphosis in two distant Drosophila species

Complete metamorphosis of holometabolous insects is a complex biological process characterized by profound morphological, physiological, and transcriptional changes. To reveal the temporal dynamics of gene expression during this critical developmental transition, we conducted a detailed analysis of the developmental transcriptomes of two Drosophila species, Drosophila melanogaster and Drosophila virilis. We confirmed partial recapitulation of the embryonic transcriptional program in pupae, but unlike the traditional hourglass model, suggesting maximal conservation at mid-embryonic stages, at different stages of pupae we observed a more complicated pattern of alternating low and high diversity, resembling an inverted hourglass, or "spindle". This underscores the complexity of developmental processes during complete metamorphosis. Notably, recently formed genes (specific to insects) exhibit pronounced expression peaks during mid-pupal development, indicating their potential role in developmental transitions. Significance StatementThis study describes the transcriptomic dynamics of complete metamorphosis in holometabolous insects. By analyzing developmental transcriptomes of Drosophila melanogaster and Drosophila virilis, we characterize the spindle pattern of gene expression during pupal stages, contrasting with the classical hourglass model of embryogenesis. This alternating pattern of low and high transcriptional diversity highlights the unique complexity of the metamorphose processes.

developmental biology↗

bioRxiv2022

Recapitulation of the embryonic transcriptional program in insect pupae

Metamorphosis of holometabolous insects is predominantly a motionless stage, when no active feeding is observed and the body is enclosed into the pupa. These physiological properties as well as undergoing processes resemble embryogenesis since at the pupal stage organs and systems of the imago are formed. Therefore recapitulation of the embryonic expression program during pupa development could be hypothesized. To assess this hypothesis at the transcriptome level, we have performed a comprehensive analysis of the developmental datasets available in the public domain. Indeed, for most datasets, the pupal gene expression resembles the embryonic rather than the larval pattern, interrupting gradual changes of the transcriptome. Moreover, changes in the transcriptome profile during the pupa-to-imago transition are positively correlated with those at the embryo-to-larvae transition, suggesting that similar expression programs are activated. Gene sets that change their expression level during the larval stage and revert it to the embryonic-like state during the metamorphosis are enriched with genes associated with metabolism and development.

developmental biology↗