Scientists have discovered the gene that controls trunk development in vertebrates. This gene is also responsible for the long bodies of snakes. The findings, just published in the journal Developmental Cell, may also be used to develop treatments for spinal cord injuries.
All vertebrates go through the same basic stages of development, with different levels of gene expression responsible for variations such as body size. The development of the trunk, including the spinal cord, varies between species but the mechanisms involved had yet to be studied. Snakes have especially long trunks, for example, but researchers were unsure about which genes controlled this developmental process.
A research team from the Instituto Gulbenkian de Ciência in Portugal studied mice with abnormal trunk and tail lengths. They found that a gene called Oct4 was responsible for these differences in length. Oct4, already known as an important regulator of stem cells, was switched “on” when trunk development began. The gene is found in many vertebrates, including snakes and other reptiles.
The team found that the gene stayed active for a longer length of time in snakes during trunk formation when compared to other animals. By remaining active during embryonic development, the gene causes snakes to end up with a very long body and short tail. The findings solved the mystery of how snakes develop such a distinctive body type.
The researchers were able to track down the gene that controls trunk development but hadn’t expected it to be such a commonly-known gene. Oct4 had already been studied in detail for its role in stem cell regulation. Oct4 acts as a switch, turning “on” to trigger trunk development and switching “off” at the start of tail formation. In snakes, Oct4 continues to be expressed longer than normal, resulting in a unique body plan. The authors plan to further investigate these mechanisms. If Oct4 can be switched back on in humans, we may be able to regrow parts of the spinal cord after injury.
Rita Aires et al. Oct4 Is a Key Regulator of Vertebrate Trunk Length Diversity. Developmental Cell (2016).