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Dynamically-expressed prion-like proteins form a cuticle in the pharynx of Caenorhabditis elegans.

George-Raizen JB, Shockley KR, Trojanowski NF, Lamb AL, Raizen DM - Biol Open (2014)

Bottom Line: We found strong transcriptional induction during the molt of 12 of 15 previously identified abu genes encoding Prion-like (P) glutamine (Q) and asparagine (N) rich PQN proteins, as well as 15 additional genes encoding closely related PQN proteins. abu/pqn genes, which we name the abu/pqn paralog group (APPG) genes, were expressed in pharyngeal cells and the proteins encoded by two APPG genes we tested localized to the pharyngeal cuticle.Deleting the APPG gene abu-14 caused abnormal pharyngeal cuticular structures and knocking down other APPG genes resulted in abnormal cuticular function.The strong developmental regulation of the APPG genes raises the possibility that such genes would be identified in transcriptional profiling experiments in which the animals' developmental stage is not precisely staged.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.

No MeSH data available.


Related in: MedlinePlus

abu/pqn genes are induced during L4 lethargus but are not induced by a blocked unfolded protein response or in response to Pseudomonas aeruginosa strain PA14 infection.Quantitative reverse transcriptase polymerase chain reaction analysis using oligonucleotide primers that amplify abu-6, abu-7, abu-8, and abu-15. The average of four biological replicates is shown on a logarithmic scale. Error bars denote standard deviation. There is strong induction of abu-6, -7, -8 and -15 gene expression in L4 lethargus in comparison to 4-hour old adults in both wild-type and xbp-1 genetic backgrounds, but no induction in young adults in response to PA14 exposure. Treatment of xbp-1 young adults with Tunicamycin or with the vehicle 0.5% DMSO does not result in abu-6, -7, -8 and -15 gene induction. Inset shows on a magnified non-logarithmic y-axis the results of the three conditions bounded by the dotted box (the x-axis is at y = 1 on the logarithmic plot and y = 0 in the inset.).
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f04: abu/pqn genes are induced during L4 lethargus but are not induced by a blocked unfolded protein response or in response to Pseudomonas aeruginosa strain PA14 infection.Quantitative reverse transcriptase polymerase chain reaction analysis using oligonucleotide primers that amplify abu-6, abu-7, abu-8, and abu-15. The average of four biological replicates is shown on a logarithmic scale. Error bars denote standard deviation. There is strong induction of abu-6, -7, -8 and -15 gene expression in L4 lethargus in comparison to 4-hour old adults in both wild-type and xbp-1 genetic backgrounds, but no induction in young adults in response to PA14 exposure. Treatment of xbp-1 young adults with Tunicamycin or with the vehicle 0.5% DMSO does not result in abu-6, -7, -8 and -15 gene induction. Inset shows on a magnified non-logarithmic y-axis the results of the three conditions bounded by the dotted box (the x-axis is at y = 1 on the logarithmic plot and y = 0 in the inset.).

Mentions: The subset of the PQN proteins that were renamed ABU have been described as being “Activated by a Blocked Unfolded protein response” (Urano et al., 2002; Sun et al., 2011). This name is based on the observation of increased expression in response to ER stress in animals mutant for xbp-1, which is required for the canonical unfolded protein response. Induction of these same abu genes has been observed with a number of other perturbations (Viswanathan et al., 2005; Haskins et al., 2008; Mair et al., 2011; Sun et al., 2011; Sahu et al., 2012). The degree of transcriptional induction of the abu genes in those experiments was modest, in some cases between 1.5-fold and 2.0-fold (see supplementary material Table S7 for complete comparison). The strong developmental regulation we observe of the APPG genes and the high levels of expression suggested to us that inadvertent inclusion of small numbers of molting animals is sufficient to account for the reported observations. For instance, 0.5% enrichment in L4 lethargus animals in a population that is otherwise made up of young adults or of mid L4 animals would result in an overall approximately two-fold higher expression of abu-7. Indeed, statistical comparisons of the published data sets reveal significant overlap between these abu-containing gene sets and our L4L gene set (supplementary material Table S8). Notably, the overlap extends to non-APPG genes also induced by these perturbations (examples given in supplementary material Table S7). While we observed strong abu gene induction during the molt in both wild-type animals and xbp-1 mutants (Fig. 4), we did not observe the previously reported induction of four abu genes in xbp-1 mutant young adult animals that were carefully staged to avoid the L4 molt (Fig. 4). Similarly, we did not observe the reported induction of abu gene expression with exposure of young adult animals to the pathogenic Pseudomonas aeruginosa bacterial strain PA14 (Fig. 4).


Dynamically-expressed prion-like proteins form a cuticle in the pharynx of Caenorhabditis elegans.

George-Raizen JB, Shockley KR, Trojanowski NF, Lamb AL, Raizen DM - Biol Open (2014)

abu/pqn genes are induced during L4 lethargus but are not induced by a blocked unfolded protein response or in response to Pseudomonas aeruginosa strain PA14 infection.Quantitative reverse transcriptase polymerase chain reaction analysis using oligonucleotide primers that amplify abu-6, abu-7, abu-8, and abu-15. The average of four biological replicates is shown on a logarithmic scale. Error bars denote standard deviation. There is strong induction of abu-6, -7, -8 and -15 gene expression in L4 lethargus in comparison to 4-hour old adults in both wild-type and xbp-1 genetic backgrounds, but no induction in young adults in response to PA14 exposure. Treatment of xbp-1 young adults with Tunicamycin or with the vehicle 0.5% DMSO does not result in abu-6, -7, -8 and -15 gene induction. Inset shows on a magnified non-logarithmic y-axis the results of the three conditions bounded by the dotted box (the x-axis is at y = 1 on the logarithmic plot and y = 0 in the inset.).
© Copyright Policy - open-access
Related In: Results  -  Collection

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f04: abu/pqn genes are induced during L4 lethargus but are not induced by a blocked unfolded protein response or in response to Pseudomonas aeruginosa strain PA14 infection.Quantitative reverse transcriptase polymerase chain reaction analysis using oligonucleotide primers that amplify abu-6, abu-7, abu-8, and abu-15. The average of four biological replicates is shown on a logarithmic scale. Error bars denote standard deviation. There is strong induction of abu-6, -7, -8 and -15 gene expression in L4 lethargus in comparison to 4-hour old adults in both wild-type and xbp-1 genetic backgrounds, but no induction in young adults in response to PA14 exposure. Treatment of xbp-1 young adults with Tunicamycin or with the vehicle 0.5% DMSO does not result in abu-6, -7, -8 and -15 gene induction. Inset shows on a magnified non-logarithmic y-axis the results of the three conditions bounded by the dotted box (the x-axis is at y = 1 on the logarithmic plot and y = 0 in the inset.).
Mentions: The subset of the PQN proteins that were renamed ABU have been described as being “Activated by a Blocked Unfolded protein response” (Urano et al., 2002; Sun et al., 2011). This name is based on the observation of increased expression in response to ER stress in animals mutant for xbp-1, which is required for the canonical unfolded protein response. Induction of these same abu genes has been observed with a number of other perturbations (Viswanathan et al., 2005; Haskins et al., 2008; Mair et al., 2011; Sun et al., 2011; Sahu et al., 2012). The degree of transcriptional induction of the abu genes in those experiments was modest, in some cases between 1.5-fold and 2.0-fold (see supplementary material Table S7 for complete comparison). The strong developmental regulation we observe of the APPG genes and the high levels of expression suggested to us that inadvertent inclusion of small numbers of molting animals is sufficient to account for the reported observations. For instance, 0.5% enrichment in L4 lethargus animals in a population that is otherwise made up of young adults or of mid L4 animals would result in an overall approximately two-fold higher expression of abu-7. Indeed, statistical comparisons of the published data sets reveal significant overlap between these abu-containing gene sets and our L4L gene set (supplementary material Table S8). Notably, the overlap extends to non-APPG genes also induced by these perturbations (examples given in supplementary material Table S7). While we observed strong abu gene induction during the molt in both wild-type animals and xbp-1 mutants (Fig. 4), we did not observe the previously reported induction of four abu genes in xbp-1 mutant young adult animals that were carefully staged to avoid the L4 molt (Fig. 4). Similarly, we did not observe the reported induction of abu gene expression with exposure of young adult animals to the pathogenic Pseudomonas aeruginosa bacterial strain PA14 (Fig. 4).

Bottom Line: We found strong transcriptional induction during the molt of 12 of 15 previously identified abu genes encoding Prion-like (P) glutamine (Q) and asparagine (N) rich PQN proteins, as well as 15 additional genes encoding closely related PQN proteins. abu/pqn genes, which we name the abu/pqn paralog group (APPG) genes, were expressed in pharyngeal cells and the proteins encoded by two APPG genes we tested localized to the pharyngeal cuticle.Deleting the APPG gene abu-14 caused abnormal pharyngeal cuticular structures and knocking down other APPG genes resulted in abnormal cuticular function.The strong developmental regulation of the APPG genes raises the possibility that such genes would be identified in transcriptional profiling experiments in which the animals' developmental stage is not precisely staged.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.

No MeSH data available.


Related in: MedlinePlus