APR 22, 2022 4:22 AM PDT

A Missing Link Between Prokaryotes and Eukaryotes is Found

WRITTEN BY: Carmen Leitch

Prokaryotic cells, which include all bacteria and archaea, are ancient, and relatively simple compared to eukaryotic cells, which are found in fungi, plants, and animals. Scientists have long sought to understand how eukaryotes evolved from simple prokaryotes, which lack organelles. It's been thought that the mitochondrial organelle comes from a symbiosis event in which two bacterial cells came together. Eukaryotes may have evolved from a cell containing a mitochondria that then merged with an archaeal cell, but there has been little direct evidence of such an organism, especially because microbes don't leave fossils that are easy to trace.

Image credit: Pixabay/Steppinstars

The Asgard archaea superphylum has been proposed as the prokaryote that bears the most similarity to eukaryotes, in part because they carry genes that were once thought to only be found in the genomes of eukaryotes.

In new research reported in Science Advances, investigators have assessed the X-ray structures of Asgard tubulin proteins, obtained from live samples of a type of archaea called Odinarchaeota, which live near hydrothermal vents.

Almost all bacteria and archaea are thought to carry a protein called FtsZ, which is involved in cell division in bacteria. FtsZ is a homolog of tubulin, which is essential to organization in eukaryotic cells, and helps separate chromosomes during eukaryotic cell division.

Two genes that were predicted to encode for FtsZ were found in the Odinarchaeota genome, along with another gene the researchers have named OdinTubulin. The protein OdinTubulin encodes for has more in common with the eukaryotic tubulin protein than it does with the prokaryotic FtsZ protein.

How sexual reproduction evolved from asexual reproduction in prokaryotes, has long been a mystery. Most prokaryotes have a circular genome that is simply copied and then put into a daughter cell, while the replication of chromosomes, and the careful segregation of the new copies into two new cells is far more complex in eukaryotes. This research helps bridge that gap.

"These new Asgard archaeal proteins, which the scientists have named OdinTubulin, in another shout-out to the Norse pantheon, are similar to both eukaryotic tubulins and prokaryotic FtsZ proteins," noted study co-author Samson Ali of Nagoya University and Okayama University.

"OdinTubulin may therefore represent an evolutionary intermediate between prokaryotic FtsZ and eukaryotic microtubule-forming tubulins," added study co-author Linh T. Tran of Okayama University.

Sources: Tokyo Institute of Technology, Science Advances

About the Author
BS
Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
MAY 07, 2022
Drug Discovery & Development
Ibuprofen and Blood Pressure Medication Linked to Kidney Damage
MAY 07, 2022
Ibuprofen and Blood Pressure Medication Linked to Kidney Damage
A combination of ibuprofen and certain blood pressure medications could lead to acute kidney injury. The corresponding s ...
MAY 10, 2022
Immunology
A Failed Immunotherapy Trial Leads to a Crucial Discovery
MAY 10, 2022
A Failed Immunotherapy Trial Leads to a Crucial Discovery
Immunotherapies, which boost a patient's immune system so it's better at fighting cancer, have been a game-chang ...
MAY 13, 2022
Drug Discovery & Development
Promising New Treatment for Cat Litter Parasite T. Gondii
MAY 13, 2022
Promising New Treatment for Cat Litter Parasite T. Gondii
Researchers have discovered a promising therapy for those suffering from toxoplasmosis, a disease caused by a parasite l ...
JUN 06, 2022
Drug Discovery & Development
Express Media Service Q&A with Sheng Li, PhD., FUJIFILM Irvine Scientific
JUN 06, 2022
Express Media Service Q&A with Sheng Li, PhD., FUJIFILM Irvine Scientific
FUJIFILM Irvine Scientific sat down with Sheng Li, PhD, Program Manager, to speak about our rapid service for small-scal ...
MAY 19, 2022
Neuroscience
Fruits and Vegetables May Reduce ADHD Symptoms in Children
MAY 19, 2022
Fruits and Vegetables May Reduce ADHD Symptoms in Children
Diets rich in fruits and vegetables may help reduce inattention issues in children with Attention deficit hyperactivity ...
JUN 03, 2022
Cell & Molecular Biology
Poultry Vaccine Led to Increase in Antibiotic Resistance in Salmonella
JUN 03, 2022
Poultry Vaccine Led to Increase in Antibiotic Resistance in Salmonella
The Salmonella bacterium is a common cause of foodborne illness, and it isn't unusual to find strains of the microbe in ...
Loading Comments...