Norman J et al. (2000) Midwest Worm Meeting "Using RNAi to study SKN-1 and other homologs governing early nematode development"

Norman J, Montgomery MK, Bishop E

[Midwest Worm Meeting, 2000]

We are interested in determining to what extent the pathways that govern blastomere identity and fates in the early embryo have been conserved between C. elegans and related nematode species, including the closely related C. briggsae and more distantly related Acrebeloides nanus (formerly,Cephalobus sp). We have been using the reverse genetic technique of dsRNA-mediated interference (RNAi) to disrupt the activity of a number of homologous genes. For some of these genes (hlh-1, glp-1, par-3, skn-1) the phenotypes obtained by RNAi knockdown are similar or identical for both C. elegans and C. briggsae, indicating that gene function has been conserved. For example, skn-1 (RNAi) embryos of C. briggsae lack gut and produce excess hypodermis, a phenotype similar to genetic skn-1 loss-of-function C. elegans mutants. We have also closely examined the phenocopies of skn-1 (RNAi) C. elegans embryos, particularly for (lack of) gut differentiation, as the strongest skn-1 mutant allele (zu67) may not be null, and have performed in situ hybridization on both skn-1 (RNAi) and skn-1 (zu67) animals. We are also using feeding protocols and heat shock promoters to deliver dsRNA at later stages of development in an attempt to further differentiate maternal from zygotic functions. Furthermore, by testing the ability of cloned homologs from one nematode species to interfere with gene activity in another species, we have observed species and strain differences in susceptibility to RNAi cross-interference, with C. briggsae appearing more sensitive than C. elegans. We have used cross-interference to our advantage to knockdown actin gene function in another nematode species, A. nanus. We are now using degenerate PCR and RNAi to clone and study genes of interest from A. nanus, which displays some developmental characteristics significantly different from those of C. elegans and C. briggsae. These differences include specification of the gut through negative inductive interactions and an ability to regulate and may represent a more primitive (i.e, ancestral) mode of development (see Wiegner & Schierenberg (1998) Dev Biol 204, 3-14).

J Norman et al. (1999) International C. elegans Meeting "RNAi: how low can you go?"

J Norman, K Galey, MK Montgomery

[International C. elegans Meeting, 1999]

We are aiming to determine the minimal sequence required to obtain effective disruption of gene function with the reverse genetic technique RNAi (RNA interference) 1 . We are approaching this problem by cloning homologs of C. elegans genes with known mutant phenotypes from the closely related C. briggsae . Subclones with known length and percent sequence identity are used to create templates for double-stranded RNA (dsRNA). The dsRNAs from the C. briggsae subclones are then introduced into C. elegans by either injection or soaking. Progeny are examined for the appropriate mutant phenotypes and processed for in situ hybridization to determine loss of the endogenous message. The effectiveness of relatively short sequences (60-300 bp) between 70 and 90% sequence identity is then compared with the effectiveness of the same sequences from C. elegans (thus, same size but close to 100% sequence identity between the interfering RNA and the target). We are primarily focusing on maternally expressed genes ( ama-1, glp-1, skn-1 ), but are also testing zygotic genes (e.g. hlh-1 ) to assess stage-related differences. Our results should be useful for designing effective RNAi strategies for both C. elegans and other nematode species. Ultimately, we hope to use RNAi as a tool to study gene function in genetically less tractable species, such as Cephalobus , in order to do comparative studies of maternal genes controlling embryonic cell fates. 1 Fire et al. 1998 Nature 391: 806-11

Norman KR et al. (2002) J Cell Biol "Alpha spectrin is essential for morphogenesis and body wall muscle formation in Caenorhabditis elegans."

Moerman DG, Norman KR

[J Cell Biol, 2002]

A common feature of multicellular animals is the ubiquitous presence of the spectrin cytoskeleton. Although discovered over 30 yr ago, the function of spectrin in nonerythrocytes has remained elusive. We have found that the spc-1 gene encodes the only alpha spectrin gene in the Caenorhabditis elegans genome. During embryogenesis, a spectrin localizes to the cell membrane in most if not all cells, starting at the first cell stage. Interestingly, this localization is dependent on beta spectrin but not beta(Heavy) spectrin. Furthermore, analysis of spc-1 mutants indicates that beta spectrin requires a spectrin to be stably recruited to the cell membrane. Animals lacking functional a spectrin fail to complete embryonic elongation and die just after hatching. These mutant animals have defects in the organization of the hypodermal apical actin cytoskeleton that is required for elongation. in addition, we find that the process of elongation is required for the proper differentiation of the body wall muscle. Specifically, when compared with myofilaments in wild-type animals the myofilaments of the body wall muscle in mutant animals are abnormally oriented relative to the longitudinal axis of the embryo, and the body wall muscle cells do not undergo normal cell shape changes.

Baylis HA (2005) Cell "VAV's got rhythm."

Baylis HA

[Cell, 2005]

Biological rhythms with periods of less than a day are physiologically important but poorly understood. In this issue of Cell, Norman, Maricq, and colleagues (Norman et al., 2005) show that VAV-1, a guanine nucleotide exchange factor for Rho-family GTPases, is necessary for three rhythmic behaviors in the nematode Caenorhabditis elegans: feeding, defecation, and ovulation.

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