Undergraduate authors

Brandeis is proud of its tradition of undergraduates working in science labs,  alongside grad students, staff and postdocs. This work often leads to publications in the primary scientific literature (see list of undergraduate publications).

The most recent of these, by Nicholas Hornstein and collaborators in the Griffith lab, appears in the Journal of Visualized Experiments. This new journal focuses on using streaming video to provide access to high quality demonstrations of lab procedures (in this case, demonstrating dissection technique for doing neurophysiology in Drosophila larvae).

Drosha and Pasha

No, this isn’t a Russian short story.

Lead authors postdoc alum Sebastian Kadener and Mol Cell Biol graduate student Joe Rodriguez and their coworkers used tiling arrays to look for targets of the enzyme Drosha in “Genome-wide identification of targets of the drosha–pasha/DGCR8 complex”, a paper recently published in the journal RNA. Drosha is a type III RNAse that is involved in the processing of  miRNAs. This paper demonstrates for first time that this enzyme is not only involved in miRNA processing, but can also process mRNAs.  Interestingly, the best example of an mRNA processed by Drosha is the mRNA that encodes another miRNA processing enzyme, the protein Pasha. As this is a partner of Drosha (the two proteins work together), the findings suggest that  there is a feedback loop that controls the abundance of the miRNA processing machinery and probably the abundance of miRNAs themselves.

Nanomaterials in cells

From Bing Xu, one of the new faculty members in the Chemistry Department here at Brandeis, comes a new review on Applications of nanomaterials inside cells. Quantum dots, magnetic nanoparticles, nanowires, the works.

Chloride channels and antiport mechanism

In a new paper in Journal of General Physiology, Brandeis postdoc Hyun-Ho Lim and Professor Christopher Miller examine the detailed mechanism by which a chloride transporter protein works. In particular, this protein does a rather crazy thing: it stoichiometrically swaps a proton on one side of the membrane for two Cl- ions on the other, and countertransports them across the membrane.  In this work, the authors identify a special glutamate residue on the cytoplasmic side of the protein that is responsible for picking up protons on that side in order to carry out this “antiport” mechanism.  (That glutamate is indicated by the spacefilled residue with red oxygen atoms in this depiction of the dimeric protein.)

Is my DNA fixed yet?

A broken chromosome (a double-strand DNA break) activates the DNA damage checkpoint to prevent cells from carrying out mitosis until the break has been repaired.  Repair of the break involves the modification and the removal of histone protein octamers from DNA around the break and these must be reestablished when repair is complete.  In a new paper in PNAS, Brandeis alumnus Jung-Ae Kim (Ph.D., Molecular and Cell Biology, 2008) and Professor James Haber show that when two of the major histone chaperone protein complexes (Asf1 and CAF-1) are deleted in yeast cells, their absence prevents cells from turning off the DNA damage checkpoint and hence cells stay permanently arrested.   These results suggest that cells specifically monitor the re-establishment of normal chromatin status after DNA repair.

How actin networks assemble in cells

A new review article in Current Opinion in Cell Biology by Molecular and Cell Biology grad student Melissa Chesarone and Biology’s Professor Bruce Goode focuses on a group of remarkable protein machines that rapidly assemble actin polymers in cells. These factors are essential for cell division, cell movement, and cell shape determination in virtually all organisms. Their catalytic mechanisms involve intricate fast-moving parts, which enables them to construct entire actin networks in a matter of seconds.

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