Schmidt J et al. (2018) Adv Exp Med Biol "Animal Models of Machado-Joseph Disease."

Schmidt J, Schmidt T

[Adv Exp Med Biol, 2018]

Animal models are an important tool to study the pathophysiology of Machado-Joseph Disease (MJD). So far, animal models using simple organisms (like the round worm Caenorhabditis elegans or the fruit fly drosophila) but also mammalian models (mouse and even a non-human primate model) have been generated to study MJD. While simple organisms made an important contribution to the identification of pathophysiological mechanisms in MJD and were further used for modifier and screening purposes, mammalian models recapitulate major disease features of MJD in humans and are therefore a highly valuable tool for e.g. the validation of mechanisms or for pre-clinical validation of treatment approaches. Here we give an overview about the strategies which were used to model MJD and about the different models generated so far. We further highlight advantages of specific model organisms and describe the new findings which were made employing these animal models of MJD.

Diane J Schmidt et al. (2003) International Worm Meeting "The roles of cytoplasmic dynein in early embryogenesis"

William Saxton, Diane J Schmidt, Susan Strome

[International Worm Meeting, 2003]

Dynein is a minus-end-directed microtubule motor that is essential for metazoan development. To investigate dynein's roles in microtubule-mediated events in early C. elegans embryos, we are using temperature-sensitive (ts) alleles of the let-354 complementation group. The evidence that let-354 encodes dynein heavy chain (DHC-1) includes: 1) let-354 has been mapped genetically to the same region of LGI as dhc-1. 2) Two cosmids that together contain the dhc-1 gene rescue let-354 mutants. 3) The mutant phenotype of let-354(ts) embryos is similar to the phenotype observed in dhc-1(RNAi) embryos. 4) Three ts alleles of let-354 contain a base-pair substitution in dhc-1. We have performed rapid temperature-shift experiments to investigate with high temporal resolution, which events in early embryogenesis require DHC-1. At permissive temperature (150C), embryos from let-354(dominant-ts)/+ mothers or from let-354(recessive-ts) homozygous mothers undergo apparently normal development and hatch. When mothers are cultured at restrictive temperature (250C), embryos show numerous, severe defects similar to those seen in dynein(RNAi) embryos. To investigate which defects result directly from dynein inactivation, we use a thermal microscope stage controlled by Peltier devices to shift embryos from 150C to 250C in less than 1 minute. Embryos show immediate defects and this temperature response is reversible. Our temperature-shift results suggest that dynein functions to maintain cortical stability, to generate a proper bipolar spindle, and for rotation of the nascent spindle onto the correct axis in the 1-cell embryo. DHC-1 function does not appear to be required to position the spindle toward the posterior of the embryo, for anaphase separation of chromosomes, or for cytokinesis. Interestingly, after upshift of embryos, DHC-1 shows dramatic accumulation at spindle poles, as would be predicted if at restrictive temperature DHC-1 retains the ability to move to the minus ends of microtubules but cannot be released. Dominant ts mutations offer a powerful approach to temporally-regulated protein inactivation. Two of the four dominant ts alleles of let-354 change a highly conserved residue in the third P- loop of dynein heavy chain. When engineered into the dynein heavy chain of yeast, this amino acid change confers a dominant and temperature-sensitive dynein-mutant phenotype. We are currently testing whether the change can create dominant-ts alleles of other P-loop-containing proteins. (Thanks to Paul Mains, Ann Rose, Daniel Hamill, and Bruce Bowerman for let-354 alleles.)

Schmidt R et al. (2017) J Cell Biol "Two populations of cytoplasmic dynein contribute to spindle positioning in C. elegans embryos."

Schmidt R, Fielmich LE, Akhmanova A, Katrukha EA, van den Heuvel S, Grigoriev I

[J Cell Biol, 2017]

The position of the mitotic spindle is tightly controlled in animal cells as it determines the plane and orientation of cell division. Contacts between cytoplasmic dynein and astral microtubules (MTs) at the cell cortex generate pulling forces that position the spindle. An evolutionarily conserved G-GPR-1/2(Pins/LGN)-LIN-5(Mud/NuMA) cortical complex interacts with dynein and is required for pulling force generation, but the dynamics of this process remain unclear. In this study, by fluorescently labeling endogenous proteins in Caenorhabditis elegans embryos, we show that dynein exists in two distinct cortical populations. One population directly depends on LIN-5, whereas the other is concentrated at MT plus ends and depends on end-binding (EB) proteins. Knockout mutants lacking all EBs are viable and fertile and display normal pulling forces and spindle positioning. However, EB protein-dependent dynein plus end tracking was found to contribute to force generation in embryos with a partially perturbed dynein function, indicating the existence of two mechanisms that together create a highly robust force-generating system.

McGhee JD (1987) Biochemistry "Purification and characterization of a carboxylesterase from the intestine of the nematode Caenorhabditis elegans."

McGhee JD

[Biochemistry, 1987]

The major intestinal esterase from the nematode Caenorhabditis elegans has been purified to essential homogeneity. Starting from whole worms, the overall purification is 9000-fold with a 10% recovery of activity. The esterase is a single polypeptide chain of Mr 60,000 and is stoichiometrically inhibited by organophosphates. Substrate preferences and inhibition patterns classify the enzyme as a carboxylesterase (EC 3.1.1.1), but the physiological function is unknown. The sequence of 13 amino acid residues at the esterase N- terminus has been determined. This partial sequence shows a surprisingly high degree of similarity to the N-terminal sequence of two carboxylesterases recently isolated from Drosophila mojavensis [Pen, J., van Beeumen, J., & Beintema, J. J. (1986) Biochem. J. 238, 691-699].

Murakami S et al. (1999) Curr Biol "Life extension and stress resistance in Caenorhabditis elegans modulated by the tkr-1 gene."

Johnson TE, Murakami S

[Curr Biol, 1999]

In this Brief Communication, which appeared in the 14 September 1998 issue of Current Biology, the UV dose was reported erroneously. The dose reported was 20 J/m2 but the actual dose used was 0.4 J/cm2. Also, the gene formally referred to as tkr-1 has since been renamed old-1 (overexpression longevity determination).

Ramos CG et al. (2014) J Bacteriol "Retraction for Ramos et al., MtvR is a global small noncoding regulatory RNA in Burkholderia cenocepacia."

Feliciano JR, da Costa PJ, Ramos CG, Grilo AM, Leitao JH

[J Bacteriol, 2014]

Volume 195, no. 16, p. 35143523, 2013. A number of problems related to images published in this paper have been brought to our attention. Figure 1D contains duplicated images in lanes S and LE, and Fig. 4D and 6B contain images previously published in articles in this journal and in Microbiology and Microbial Pathogenesis, i.e., the following: C. G. Ramos, S. A. Sousa, A. M. Grilo, J. R. Feliciano, and J. H. Leitao, J. Bacteriol. 193:15151526, 2011. doi:10.1128/JB.01374-11. S. A. Sousa, C. G. Ramos, L. M. Moreira, and J. H. Leitao, Microbiology 156:896908, 2010. doi:10.1099/mic.0.035139-0. C. G. Ramos, S. A. Sousa, A. M. Grilo, L. Eberl, and J. H. Leitao, Microb. Pathog. 48:168177, 2010. doi: 10.1016/j.micpath.2010.02.006. Therefore, we retract the paper. We deeply regret this situation and apologize for any inconvenience to the editors and readers of Journal of Bacteriology, Microbial Pathogenesis, and Microbiology.

Nillegoda NB et al. (2015) Nature "Crucial HSP70 co-chaperone complex unlocks metazoan protein disaggregation."

Berynskyy M, Morimoto RI, Bukau B, Stengel F, Kirstein J, Szlachcic A, Arnsburg K, Stank A, Scior A, Nillegoda NB, Gao X, Guilbride DL, Aebersold R, Wade RC, Mayer MP

[Nature, 2015]

Protein aggregates are the hallmark of stressed and ageing cells, and characterize several pathophysiological states. Healthy metazoan cells effectively eliminate intracellular protein aggregates, indicating that efficient disaggregation and/or degradation mechanisms exist. However, metazoans lack the key heat-shock protein disaggregase HSP100 of non-metazoan HSP70-dependent protein disaggregation systems, and the human HSP70 system alone, even with the crucial HSP110 nucleotide exchange factor, has poor disaggregation activity in vitro. This unresolved conundrum is central to protein quality control biology. Here we show that synergic cooperation between complexed J-protein co-chaperones of classes A and B unleashes highly efficient protein disaggregation activity in human and nematode HSP70 systems. Metazoan mixed-class J-protein complexes are transient, involve complementary charged regions conserved in the J-domains and carboxy-terminal domains of each J-protein class, and are flexible with respect to subunit composition. Complex formation allows J-proteins to initiate transient higher order chaperone structures involving HSP70 and interacting nucleotide exchange factors. A network of cooperative class A and B J-protein interactions therefore provides the metazoan HSP70 machinery with powerful, flexible, and finely regulatable disaggregase activity and a further level of regulation crucial for cellular protein quality control.

Miller DM et al. (1992) Worm Breeder's Gazette "unc-4 LacZ Expression in A-Type Motor Neurons"

Miller DM, Niemeyer CJ

[Worm Breeder's Gazette, 1992]

unc-4 LacZ expression in A-type motor neurons David M. Miller and Charles J. Niemeyer, Dept. of Cell Biology, Duke Univ. Medical Ctr, Durham, NC 27710

Sommer RJ et al. (1994) Worm Breeder's Gazette "Evolution of Vulva-Formation: Part II: Species With a Central Vulva"

Sommer RJ, Sternberg PW

[Worm Breeder's Gazette, 1994]

Evolution of vulva-formation: Part II: Species with a central vulva Ralf J. Sommer & Paul W. Sternberg, California Institute of Technology, Division of Biology 156-29, Pasadena, CA 91125

Jun-ichi Aikawa (2001) International C. elegans Meeting "Molecular characterization of heparan sulfate/heparin N-deacetylase/N-sulfotransferase in worms"

Jun-ichi Aikawa

[International C. elegans Meeting, 2001]

Heparan sulfate binds and activates a large variety of growth factors, enzymes and extracellular matrix proteins. These interactions largely depend on the specific arrangement of sulfated moieties and uronic acid epimers within the chains. These oligosaccharide sequences are generated in a step-wise manner, initiated by the formation of a linkage tetrasaccharide which is then extended by copolymerization of alternating a1,4GlcNAc and b1,4GlcA residues. As the chains polymerize, they undergo a series of sulfation and epimerization reactions. The first set of modifications involves the removal of acetyl units from subsets of GlcNAc residues, and the addition of sulfate groups to the resulting free amino groups. These reactions are catalyzed by a family of enzymes designated as GlcNAc N-deacetylase/N-sulfotransferases (NDST), since they simultaneously. Four members of the family have been identified in vertebrates, with single orthologs present in Drosophila and C. elegans. We have revealed tissue-specific expression pattern and unique enzymatic properties of these four isozymes1,2). In fly, loss of NDST (sulfateless) results in unsulfated chains and defective signaling by multiple growth factors and morphogens. I reconstituted cDNA for worm NDST from EST clones and 5' RACE products. Enzymatic activities will be discussed. 1) Aikawa, J. & Esko, J. D J. Biol. Chem. 274, 2690-2695 (1999) 2) Aikawa, J., Grobe, K., Tsujimoto, M. & Esko, J. D J. Biol. Chem. 276, 5876-5882 (2001)