Download Cindy Spangler

Cindy Spangler
Biol 405
March 22, 2006
Journal Club 2
What was the question being investigated?
Eukaryote cells are able to maintain certain cell shapes by intermediate filament proteins
that build the cytoskeleton of a cell. But what causes prokaryotes cells to form spheres,
rods, and helical, etc. shapes? What proteins build the cytoskeleton of prokaryotes and
give them the different shapes? And how does this protein work?
What were the results of the authors’ experiments and their conclusions?
1. Library of random trasposon (Tn5) insertion C. crescentus mutants were visually
screened to find straight rod morphology. Two independent Tn5 insertions were
mapped and a polar effect on downstream gene expression by the Tn5 was
determined not to affect the morphology. The Tn5 was determined that with creS
mutation introduction resulted in the mutation. With an introduction of a wild
type plasmid into the mutant, morphology was restored. creS is necessary for
prokaryote cell morphology.
2. Crescentin was flagged and mapped by immunofluorescence microscopy with
anti-FLAG antibodies on cells stained with DAPI. The creS formed a pole to pole
filament along the side of the cell. This maps were the crescentin is so that the
determination of shape can be seen.
3. The localization was tested using different copies of the creS strain introduced to
the cell as the only copies. Without the wild type, the introduced creS was not
functional and the position of the protein is important to cell structure.
4. The sequence of the crescentin has various similarities that cytokertain. The
proteins are rich in coiled coil motifs and share similarities with the IF proteins.
This is important because the link between the two proteins and the structure.
What was the key experiment?
The coiled-coil experiment is the most important one because the link between how the
crescetin works is related to the cytokertain that is in eukaryote cells. This structural
similarity show that the proteins that form the structures of cells are similar in both
eukaryote and prokaryote.
What is the next experiment?
The next experiment should look at if there is only the crescetin as one of the two
structural elements and see what mutations would be necessary to form the same
functional structures in eukaryotes. And if crescetin could be used in eukaryotes.