@article {381,
	title = {Silencing of a putative inner arm dynein heavy chain results in flagellar immotility in Trypanosoma brucei.},
	journal = {Mol Biochem Parasitol},
	volume = {175},
	year = {2011},
	month = {2011 Jan},
	pages = {68-75},
	abstract = {The Trypanosoma brucei flagellum controls motility and is crucial for cell polarity and division. Unique features of trypanosome motility suggest that flagellar beat regulation in this organism is unusual and worthy of study. The flagellar axoneme, required for motility, has a structure that is highly conserved among eukaryotes. Of the several dyneins in the axonemal inner arm complex, dynein f is thought to control flagellar waveform shape. A T. brucei gene predicted to encode the dynein f alpha heavy chain, TbDNAH10, was silenced using RNA interference in procyclic T. brucei cells. This resulted in immotile flagella, showing no movement except for occasional slight twitches at the tips. Cell growth slowed dramatically and cells were found in large clusters. Microscopic analysis of silenced cultures showed many cells with detached flagella, sometimes entangled between multiple cells. DAPI staining showed an increased frequency of mis-positioned kinetoplasts and multinucleate cells, suggesting that these cells experience disruption at an early cell cycle stage, probably secondary to the motility defect. TEM images showed apparently normal axonemes and no discernable defects in inner arm structure. This study demonstrates the use of RNAi as an effective method to study very large genes such as dynein heavy chains (HCs), and the immotility phenotype of these dynein knockdowns suggests that an intact inner arm is necessary for flagellar beating in T. brucei. Since analogous mutants in Chlamydomonas reinhardtii retain motility, this phenotype likely reflects differences in requirements for motility and/or dynein assembly between the two organisms and these comparative studies will help elucidate the mechanisms of flagellar beat regulation.},
	keywords = {Cell Nucleus, Dyneins, Flagella, Locomotion, Microscopy, Electron, Transmission, Organelles, Protozoan Proteins, RNA Interference, Trypanosoma brucei brucei},
	issn = {1872-9428},
	doi = {10.1016/j.molbiopara.2010.09.005},
	author = {Springer, Amy L and Bruhn, David F and Kinzel, Kathryn W and Rosenthal, No{\"e}l F and Zukas, Randi and Klingbeil, Michele M}
}
@article {809,
	title = {Single molecule analysis of a red fluorescent RecA protein reveals a defect in nucleoprotein filament nucleation that relates to its reduced biological functions.},
	journal = {J Biol Chem},
	volume = {284},
	year = {2009},
	month = {2009 Jul 10},
	pages = {18664-73},
	abstract = {Fluorescent fusion proteins are exceedingly useful for monitoring protein localization in situ or visualizing protein behavior at the single molecule level. Unfortunately, some proteins are rendered inactive by the fusion. To circumvent this problem, we fused a hyperactive RecA protein (RecA803 protein) to monomeric red fluorescent protein (mRFP1) to produce a functional protein (RecA-RFP) that is suitable for in vivo and in vitro analysis. In vivo, the RecA-RFP partially restores UV resistance, conjugational recombination, and SOS induction to recA(-) cells. In vitro, the purified RecA-RFP protein forms a nucleoprotein filament whose k(cat) for single-stranded DNA-dependent ATPase activity is reduced approximately 3-fold relative to wild-type protein, and which is largely inhibited by single-stranded DNA-binding protein. However, RecA protein is also a dATPase; dATP supports RecA-RFP nucleoprotein filament formation in the presence of single-stranded DNA-binding protein. Furthermore, as for the wild-type protein, the activities of RecA-RFP are further enhanced by shifting the pH to 6.2. As a consequence, RecA-RFP is proficient for DNA strand exchange with dATP or at lower pH. Finally, using single molecule visualization, RecA-RFP was seen to assemble into a continuous filament on duplex DNA, and to extend the DNA approximately 1.7-fold. Consistent with its attenuated activities, RecA-RFP nucleates onto double-stranded DNA approximately 3-fold more slowly than the wild-type protein, but still requires approximately 3 monomers to form the rate-limited nucleus needed for filament assembly. Thus, RecA-RFP reveals that its attenuated biological functions correlate with a reduced frequency of nucleoprotein filament nucleation at the single molecule level.},
	keywords = {Cell Nucleus, DNA, DNA, Single-Stranded, Escherichia coli, Hydrogen-Ion Concentration, Kinetics, Luminescent Proteins, Nucleoproteins, Plasmids, Protein Binding, Rec A Recombinases, Recombination, Genetic, Sensitivity and Specificity, Ultraviolet Rays},
	issn = {0021-9258},
	doi = {10.1074/jbc.M109.004895},
	author = {Handa, Naofumi and Amitani, Ichiro and Gumlaw, Nathan and Sandler, Steven J and Kowalczykowski, Stephen C}
}
