Christine Jacobs-Wagner (Yale, HHMI) 2: DNA segregation & active intracellular transport in bacteria

www.ibiology.org/microbiology...
Talk Overview:
Most bacterial cells are many, many times smaller than eukaryotic cells. Since they have no membrane-bound internal organelles, their cellular organization also appears much simpler. Over the last decade, however, scientists have come to understand that that bacterial cells have a cytoskeleton. Jacobs-Wagner explains that bacterial homologues of tubulin (FtsZ) and actin (MreB) are critical for cell division amongst other functions. Crescentin, a bacterial counterpart of intermediate filament proteins, gives Caulobacter crescentus its crescent shape. In addition, bacteria exhibit sophisticated spatial organization; proteins can be spatially patterned and the bacterial chromosome forms an organized structure that locates genes at specific positions in the cell.
In her second lecture, Jacobs-Wagner tells us about research in her lab into how bacterial chromosomal DNA is segregated. For distances as small as those found in a bacterial cell, diffusion can successfully distribute high copy number molecules throughout the cell. However, diffusion cannot effectively separate 2 chromosomes such that after cell division each daughter cell is likely to have one chromosome. To do this job, bacteria have evolved a partitioning system called ParABS. Jacobs-Wagner describes the how the ParABS system works to separate chromosomal DNA in C. crescentus.
Speaker Biography:
Christine Jacobs-Wagner received her BS in biochemistry from the University of Liège in Belgium and her PhD from the University of Liège and the Karolinska Institute. As a post-doctoral fellow she worked with Lucy Shapiro at Stanford University. In 2001, Jacobs-Wagner moved to Yale University where she is currently a Professor of Molecular, Cellular and Developmental Biology and Director of the Microbial Sciences Institute. Jacobs-Wagner also has been a Howard Hughes Medical Institute Investigator since 2008. Her lab investigates the spatial and temporal organization of molecules inside bacteria and the impact of this organization on bacterial function and behavior.
Jacobs-Wagner’s pioneering research has been recognized with a Pew Scholar Award, the American Society for Cell Biology Women in Cell Biology Junior Award, and the Eli Lilly Award from the American Society of Microbiology.

[@ilmarinen79]

Fascinating. I really love these 'next gen' simulation animations.

[@numericalcode]

These are deep, fundamental questions.

[@vantinhnguyen9297]

Helpful video! thank you so much!

[@yangliu1985]

This is helpful! Especially the simulation

[@palomafuentesrobert9617]

Thanks!!!! it was a very helpful and clear video!!

[@myambition2313]

awesome video!!!!

[@williamholmberg6692]

Hi, is there a video on ParMRC (type II)? or could someone explain it to me?

[@kseniaalexandrova5298]

Thank you for your lectures! Lectures are really helpful for exam preparation on the same topic!

[@genegray9895]

It's fascinating that bacteria use their DNA as a cytoskeleton with seemingly all of the same abilities as eukaryotic cells. I'm curious if there are cell behaviors that are chemically organized at smaller spatial scales by the DNA.

[@Manava2012]

Why Should only one partition complex diffuse?

[@imh3r3now1]

+Does itMatter One of the ParB-parS complexes is attached to the old pole by a semi-understood complex of proteins. The mechanism by which the second partition complex avoids also being tethered to the old pole is not known as far as I'm aware, but I would assume it is simply stoichiometric (i.e. there is only "space" for one partition complex to bind). I make this assumption because I know that the second partition complex actually is also tethered (by several proteins, including TipN) once it reaches the new pole.

[@videosformybrain3606]

very good, i have a huge crush now.