The mystery strain 1-9 contains the CDC10 gene from Saccharomyces cerevisiae, a non-essential gene whose systematic name is YCR002C. The gene is made of 969 base pairs, with a guanine-cytosine percentage of 37.05%. It is situated on the third chromosome, at position 118348..117380.
The gene produces the Cdc10 protein (cell division protein 10), which has 177 known interactors, and possibly more. This protein has 322 amino acids and is 37016.2 Da. The protein amount increases if the cell is under stress. The cell division protein 10 is necessary for cytokinesis, as it is needed to make a septin ring around the neck of a forming bud.
The N-terminus of the cell division protein 10 interacts with phosphatidylinositol-4,5-bisphosphate (PIP2), which is a phospholipid component of the cell membranes and is part of cellular signalling pathways. PIP2 binds to the septin’s polybasic motif, hence bringing the septin monomers to the membrane surface, allowing rings to be formed.Septins are GTP-binding proteins that were first found in yeasts and then later found in other species, such as humans. They are conserved in many species, including humans, mice, chicken S. cerevisiae, N.
pombe and frogs.There are four septin genes in yeast (CDC3, CDC10, CDC11 and CDC12), and these genes have many functions, such as cytokinesis, morphogenesis, chitin deposition, cell cycle regulation and stopping any diffusion of proteins that might occur between the mother and the daughter.Septins play a role in cytokinesis by making a ring around the connection between the mother and the bud neck. The ring is made 15 minutes before the bud appears, and the ring then becomes a collar made out of cortical filaments.
These filaments were made by rod-like hetero-oligomers of the CDC3, CDC10, CDC11, CDC12 and possibly the SHS1 genes which interacted with each other, and are dependent on protein kinases like GIN4 and CLA4. The CDC10 that is fundamental in order to make the paired filaments by bundling up the polymers. Once cytokinesis occurs, the collar becomes two rings, and these rings function as a scaffold, allowing different components that are necessary for the cell cycle to come, or for some proteins to bind to it in order to progress in the cell cycle.If there is a mutation in one of the septin genes, it is still possible for cytokinesis to occur even if the filaments do not function properly, meaning that these filaments are not essential for cytokinesis.