The Chinmo gene establishes the juvenile stage in insects, according to a
recent study that was led by the Institute for Evolutionary Biology (IBE,
CSIC-UPF) and the IRB Barcelona and published on eLife. Additionally, it
demonstrates that the Br-C and E93 genes control insect maturity. These
genes, which are also found in humans, promote and repress carcinogenic
processes, respectively.
These genes have been preserved throughout insect evolution, according to
the research, which used the fruit fly Drosophila melanogaster and the
cockroach Blatella germanica. As a result, it is thought that they could be
crucial in the development of metamorphosis.
In insects, the biological clock's hands are the Chinmo, Br-C, and E93
genes.
The embryo, which develops inside the egg, the larva (juvenile stage),
which grows in several phases, and the pupa, which is the stage that
encompasses metamorphosis and the formation of the adult organism, are the
three stages of development that insects that undergo complete
metamorphosis, like flies, go through.
According to earlier research, insects' Br-C gene controls how their pupae
develop. The same IBE team that oversaw this work indicated the crucial role
of E93 in 2019 in order to finish insect metamorphosis and start the
development of the tissues that would eventually create the adult. But until
today, it was unknown which gene determined the juvenile stage. The Chimno
gene has now been determined by this study to be the primary precursor of
this stage in insects.
The authors found that by eliminating the Chinmo gene in Drosophila
specimens, these flies advanced to the pupal stage without finishing the
juvenile stage, progressing to the adult stage early. These results support
the notion that Chinmo is crucial for fetal development.
"We have shown that maintaining the cells undifferentiated throughout the
juvenile stage of Drosophila improves tissue development. Because the gene
suppresses the activity of those responsible for generating adult tissues,
cells cannot develop while Chinmo is expressed, according to Dr. Xavier
Franch, a researcher at the IBE (CSIC-UPF) who co-led the study.
The study comes to the conclusion that in order for Drosophila to
effectively transition from the juvenile to the pupal stage and complete
metamorphosis, the Chinmo gene must be inactivated. It also supports the
theory that the three genes Chinmo, Br-C, and E93, which function in
sequence throughout the larval, pupal, and adult stages, respectively,
coordinate the development of the many organs that make up the adult
organism.
Growth-regulating genes are crucial in the development of cancer.
The vast family of BTB-ZF transcription factors, which includes proteins
implicated in cancer and present in humans, includes Chinmo and Br-C.
Although earlier research had indicated that Chinmo is a precursor to
cancer, the part played by Br-C and E93 in this condition was not
recognized.
"Understanding how cells grow at the molecular level can help us understand
how cancer develops. Generate, differentiate, and mature in healthy cells.
Cancer cells, on the other hand, proliferate uncontrolled, don't
differentiate, and don't mature. Therefore, understanding the function of
Chinmo, Br-C, and E93 may be essential for future clinical research,
according to Dr. Jordi Casanova, a researcher at IRB Barcelona and a study
co-author.
According to the study, C-Br and E93 work as tumor suppressors by promoting
tissue maturation, but Chinmo is an oncogenic precursor because it
encourages tissue proliferation and hinders differentiation.
Chinmo explains the history of metamorphosis
An evolutionary invention, the entire metamorphosis of insects like
butterflies and flies has evolved through time from insects that underwent
relatively simpler metamorphoses, like cockroaches. The role of Chinmo,
Br-C, and E93 in cockroaches was examined by the researchers in order to
comprehend how this progressive process has occurred.
"We can see how evolution operates by analyzing how these genes function in
various types of insects. According to Dr. David Martin, a researcher at the
IBE (CSIC-UPF) who co-led the study, "The finding that Chinmo function is
retained in insects as evolutionarily distinct as flies and cockroaches
provides us insights as to how metamorphoses evolved.
The study's findings suggest that in more primitive insects like the
cockroach, the regulatory actions of Chinmo and E93 are adequate to control
the change from the juvenile to the adult form. However, the Br-C gene's
insertion allowed insects like flies to produce pupae and show signs of full
metamorphosis through a new pupal stage.
