Johnson AW et al. (2002) Trends Biochem Sci "Nuclear export of ribosomal subunits."

Johnson AW, Dahlberg J, Lund E

[Trends Biochem Sci, 2002]

The partitioning of cells by a nuclear envelope ensures that precursors of ribosomes do not interact prematurely with other components of the translation machinery. Ribosomal subunits are assembled in nucleoli and exported to the cytoplasm in a CRM1/Ran-GTP-dependent fashion. Export of the large (60S) subunit requires a shuttling adaptor protein, NMD3, which binds to mature, correctly folded subunits. Immature or defective particles do not bind NMD3 and thus are excluded from the export pathway. This structural proofreading is extended into the cytoplasm, where it is believed that several energy-requiring steps release shuttling factors from the subunit, allowing it to function in translation.

Ho JH et al. (1999) Mol Cell Biol "NMD3 encodes an essential cytoplasmic protein required for stable 60S ribosomal subunits in Saccharomyces cerevisiae."

Ho JH, Johnson AW

[Mol Cell Biol, 1999]

A mutation in NMD3 was found to be lethal in the absence of XRN1, which encodes the major cytoplasmic exoribonuclease responsible for mRNA turnover. Molecular genetic analysis of NMD3 revealed that it is an essential gene required for stable 60S ribosomal subunits. Cells bearing a temperature-sensitive allele of NMD3 had decreased levels of 60S subunits at the nonpermissive temperature which resulted in the formation of half-mer polysomes. Pulse-chase analysis of rRNA biogenesis indicated that 25S rRNA was made and processed with kinetics similar to wild-type kinetics. However, the mature RNA was rapidly degraded, with a half-life of 4 min. Nmd3p fractionated as a cytoplasmic protein and sedimented in the position of free 60S subunits in sucrose gradients. These results suggest that Nmd3p is a cytoplasmic factor required for a late cytoplasmic assembly step of the 60S subunit but is not a ribosomal protein. Putative orthologs of Nmd3p exist in Drosophila, in nematodes, and in archaebacteria but not in eubacteria. The Nmd3 protein sequence does not contain readily recognizable motifs of known function. However, these proteins all have an amino-terminal domain containing four repeats of Cx2C, reminiscent of zinc-binding proteins, implicated in nucleic acid binding or protein oligomerization.

Johnson, Christina K. et al. (2021) MicroPubl Biol

Miller III, David M., Johnson, Christina K., Bianchi, Laura

[MicroPubl Biol, 2021]

For Johnson, CK; Miller, DD; Bianchi, L (2021). Effect of the protease plasmin on C. elegans hyperactive DEG/ENaC channels MEC-4(d) and UNC-8(d). microPublication Biology. 10.17912/micropub.biology.000412.

Johnson TE (2005) J Gerontol A Biol Sci Med Sci "Genes, phenes, and dreams of immortality: the 2003 Kleemeier Award lecture."

Johnson TE

[J Gerontol A Biol Sci Med Sci, 2005]

The 2002 Kleemeier Award from the Gerontological Society of America was awarded to Thomas E. Johnson, PhD, of the University of Colorado at Boulder. Dr. Johnson was the pioneer who first applied genetic analyses to the study of the aging processes in Caenorhabditis elegans and who introduced the nematode as an aging model. Longer life span was chosen as a surrogate marker for slowed aging. Here Dr. Johnson describes his role(s) in the isolation of age-1, the first longevity mutant, which can more than double the life span and which slows the rate of aging more than twofold. He also reviews research suggesting conservation of function and applicability to intervention by pharmacological targeting of the Age-1 pathway. Current work by biotechnology companies targets this and other basic discoveries in an attempt to postpone human aging.

Ho JH et al. (2000) J Cell Biol "Nmd3p is a Crm1p-dependent adapter protein for nuclear export of the large ribosomal subunit."

Ho JH, Johnson AW, Kallstrom G

[J Cell Biol, 2000]

In eukaryotic cells, nuclear export of nascent ribosomal subunits through the nuclear pore complex depends on the small GTPase Ran. However, neither the nuclear export signals (NESs) for the ribosomal subunits nor the receptor proteins, which recognize the NESs and mediate export of the subunits, have been identified. We showed previously that Nmd3p is an essential protein from yeast that is required for a late step in biogenesis of the large (60S) ribosomal subunit. Here, we show that Nmd3p shuttles and that deletion of the NES from Nmd3p leads to nuclear accumulation of the mutant protein, inhibition of the 60S subunit biogenesis, and inhibition of the nuclear export of 60S subunits. Moreover, the 60S subunits that accumulate in the nucleus can be coimmunoprecipitated with the NES-deficient Nmd3p. 60S subunit biogenesis and export of truncated Nmd3p were restored by the addition of an exogenous NES. To identify the export receptor for Nmd3p we show that Nmd3p shuttling and 60S export is blocked by the Crm1p-specific inhibitor leptomycin B. These results identify Crm1p as the receptor for Nmd3p export. Thus, export of the 60S subunit is mediated by the adapter protein Nmd3p in a Crm1p-dependent pathway.

Murakami S et al. (1996) West Coast Worm Meeting "LIFE-EXTENSION PATHWAY IN C.ELEGANS"

Johnson TE, Dames SA, Murakami S, Tedesco PM, Duhon SA

[West Coast Worm Meeting, 1996]

Life extension is conferred either by mutants extending adult life (Age), including age-1, daf-2, daf-23, daf-28, spe-26, and an allele of clk-1. Another mode of life extension is conferred by mutants delaying developmental stage (Clk), including clk-1, clk-2, clk-3, gro-1(Wong et al., 1995; Lakowski and Hekimi, 1996). Three groups have identified a life-extension pathway formed by some Daf mutations (Dorman et al., 1995; Larsen et al., 1995; Murakami and Johnson, 1996). We found that the pathway is not limited to Daf mutations but includes other types of the Age mutants (Murakami and Johnson, 1996). Interestingly, the pathway confers UV resistance, suggesting that UV resistance is a good indicator of Age. It is also consistent with the hypothesis that stress resistance is a rate limiting factor determining longevity. We are also testing whether the Age-pathway can confer other types of stress such as H2O2 and heat.

Hooper C (1991) The Journal of NIH Research "Old-aged mutant ninja nematodes' cool anti-age gene."

Hooper C

[The Journal of NIH Research, 1991]

Cowabugna, dudes! Those lean, gene-revealing machines have scored a most totally excellent victory in the battle to understand aging. We are, of course, talking about mutant ninja nematodes here. At a conference on aging in January at Cold Spring Harbor's Banbury Center, Thomas Johnson of the Institute for Behavioral Genetics at the University of Colorado in Boulder brought some dudes and dudettes from Capitol Hill up to date on the latest awesome achievements of the bodacious beasts know as Caenorhabditis elegans.

Cowden C et al. (1986) Worm Breeder's Gazette "a CCK-like neuropeptide in Ascaris."

Stretton AOW, Cowden C

[Worm Breeder's Gazette, 1986]

Our aim is to obtain peptides of known sequence from Ascaris in order to determine their mode of action using electrophysiological methods. Since McIntire and Horvitz (C. elegans CSH Abstracts 1985) showed that cholecystokinin-like immunoreactivity (CCK-LI) is present in certain neurons in C. elegans, we are initially investigating the role of a CCK-like peptide (CCK-LP) in the nervous system of Ascaris using anti-CCK8 antisera to detect and localize CCK-LI. Using the methods developed by Johnson (see Johnson and Stretton, Soc. Neurosci. Abstr. 9: 302; Sithigorngul, Johnson and Stretton, C. elegans CSH Abstracts 1985) we find that in Ascaris, CCK-LI is concentrated in 2 cells (AVF cells) in the ventral nerve cord, in 3 cells in the ventral ganglion, in 4 processes in the ventral cord, and in 2 processes in the lateral line. Thus the CCK-LP is concentrated in a small minority of the 180 neurons present in the anterior region of adult Ascaris.We have developed a procedure for extracting the CCK- LP from C. elegans and fractionating the extract on a C18 cartridge. High voltage paper electrophoresis shows that added radioiodinated CCK8 is chemically intact after this extraction and after fractionation. The CCK-LP was separated from more hydrophilic components with a 20-40% gradient of acetonitrile on reversed phase HPLC. RIA's detected CCK-LI associated with a peak of optical density. Addition of authentic CCK8 (non-sulfated) to the sample showed that the RIA-positive peak was close to, but distinctly separate from, CCK8. Assuming that the specific immunoreactivity of nematode CCK-LP and mammalian CCK8 is the same, we can obtain 100 pmoles from 60g of C. elegans. From this crude estimate, it seems that the levels of recoverable peptide are sufficient for amino acid sequence determination which is now our top priority.

Coleman-Hulbert, Anna L et al. MicroPubl Biol

Sedore, Christine A, Phillips, Patrick C, Coleman-Hulbert, Anna L, Driscoll, Monica, Banse, Stephan A, Lithgow, Gordon J, Guo, Max, Johnson, Erik

[MicroPubl Biol, 2019]

The authors, Coleman-Hulbert, AL; Johnson, E; Sedore, CA; Banse, SA; Guo, M2; Driscoll, M3; Lithgow, GJ; and Phillips, PC, submit the following correction. The first reference in the methods paragraph should be (Lucanic et al., 2017; Plummer et al., 2017) and should not be letteredaccordingly. We assayed lifespan in response to imatinib mesylate exposure in three Caenorhabditis species in triplicate using our previously published workflow (Lucanic et al. 2017a; b). should be corrected to: We assayed lifespan in response to imatinib mesylate exposure in three Caenorhabditis species in triplicate using our previously published workflow (Lucanic et al., 2017; Plummer et al., 2017).

Johnson TE (2013) Exp Gerontol "25 years after age-1: genes, interventions and the revolution in aging research."

Johnson TE

[Exp Gerontol, 2013]

This communication will briefly review more than 30 years of research on aging using the nematode Caenorhabditis elegans ("The Worm") as carried out in the labs of Tom Johnson. We will highlight research directions initiated in the 1980's, which were exciting for those of us trying to turn over a new leaf in aging research. In this narrative, I will discuss primarily the science that I and my lab have been involved with for the last 30 years. This area has been fascinating to those studying the sociology of science as modern aging research has moved to replace the simplistic, poorly controlled and outright fictitious approaches seen in much of the previous aging research.