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The RHO-1 RhoGTPase modulates fertility and multiple behaviors in adult C. elegans.

McMullan R, Nurrish SJ - PLoS ONE (2011)

Bottom Line: Changes in RHO-1 signaling in cholinergic neurons affected locomotion, pharyngeal pumping and fecundity.Changes in RHO-1 signaling outside the cholinergic neurons resulted in defective defecation, ovulation, and changes in C. elegans body morphology.Finally both increased and decreased RHO-1 signaling in adults resulted in death within hours.

View Article: PubMed Central - PubMed

Affiliation: MRC Cell Biology Unit, MRC Laboratory for Molecular Cell Biology and Department of Neuroscience, Physiology and Pharmacology, University College, London, United Kingdom.

ABSTRACT
The Rho family of small GTPases are essential during early embryonic development making it difficult to study their functions in adult animals. Using inducible transgenes expressing either a constitutively active version of the single C. elegans Rho ortholog, RHO-1, or an inhibitor of endogenous Rho (C3 transferase), we demonstrate multiple defects caused by altering Rho signaling in adult C. elegans. Changes in RHO-1 signaling in cholinergic neurons affected locomotion, pharyngeal pumping and fecundity. Changes in RHO-1 signaling outside the cholinergic neurons resulted in defective defecation, ovulation, and changes in C. elegans body morphology. Finally both increased and decreased RHO-1 signaling in adults resulted in death within hours. The multiple post-developmental roles for Rho in C. elegans demonstrate that RhoA signaling pathways continue to be used post-developmentally and the resulting phenotypes provide an opportunity to further study post-developmental Rho signaling pathways using genetic screens.

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Related in: MedlinePlus

RHO-1 regulates defecation.The average defecation cycle length was determined by measuring the interval between pBoc contractions. The defecation cycle was almost completely blocked by expression of hsRHO-1(G14V) (nzIs1) but not by nRHO-1(G14V) (nzIs29). Inhibition of endogenous RHO-1 by expressing hsC3 transferase (nzEx4) resulted in increased variability in cycle length and an increase in the average defecation cycle period.
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pone-0017265-g004: RHO-1 regulates defecation.The average defecation cycle length was determined by measuring the interval between pBoc contractions. The defecation cycle was almost completely blocked by expression of hsRHO-1(G14V) (nzIs1) but not by nRHO-1(G14V) (nzIs29). Inhibition of endogenous RHO-1 by expressing hsC3 transferase (nzEx4) resulted in increased variability in cycle length and an increase in the average defecation cycle period.

Mentions: Comparison of heat shock and cholinergic expression of RHO-1(G14V) revealed roles for RHO-1 in cells other than the cholinergic motor neurons. One example is the effect of RHO-1(G14V) expression on the defecation cycle. Wild type animals defecate by initiating a series of three muscle contractions; (posterior body-wall-muscle contraction (pBoc), anterior body-wall-muscle contraction (aBoc) and enteric-muscle contraction (Emc)), regularly with an interval between cycles of 50sec [29]. Although the aBoc and Emc steps of this cycle require neuronal activity via a GABAergic motor neuron the pBoc step and initiation of the defecation cycle do not require neuronal input [45]. Expression of constitutively active hsRHO-1(G14V), but not nRHO-1(G14V) resulted in an almost complete block in initiation of the defecation cycle (as defined by the interval between pBoc) (Figure 4), however, when a cycle did occur all three motor steps (pBoc, aBoc and Emc) were observed. This suggests that RHO-1 acts in non-cholinergic cells to regulate defecation cycle initiation rather than muscle contractions themselves. Inhibition of endogenous RHO-1 in adults using hsC3 transferase also resulted in a defect in the defecation motor programme. Although the cycle was not completely blocked, as it was by overexpression of hsRHO-1(G14V), it became very variable and a slight increase in the average cycle period was observed (Figure 4).


The RHO-1 RhoGTPase modulates fertility and multiple behaviors in adult C. elegans.

McMullan R, Nurrish SJ - PLoS ONE (2011)

RHO-1 regulates defecation.The average defecation cycle length was determined by measuring the interval between pBoc contractions. The defecation cycle was almost completely blocked by expression of hsRHO-1(G14V) (nzIs1) but not by nRHO-1(G14V) (nzIs29). Inhibition of endogenous RHO-1 by expressing hsC3 transferase (nzEx4) resulted in increased variability in cycle length and an increase in the average defecation cycle period.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3046162&req=5

pone-0017265-g004: RHO-1 regulates defecation.The average defecation cycle length was determined by measuring the interval between pBoc contractions. The defecation cycle was almost completely blocked by expression of hsRHO-1(G14V) (nzIs1) but not by nRHO-1(G14V) (nzIs29). Inhibition of endogenous RHO-1 by expressing hsC3 transferase (nzEx4) resulted in increased variability in cycle length and an increase in the average defecation cycle period.
Mentions: Comparison of heat shock and cholinergic expression of RHO-1(G14V) revealed roles for RHO-1 in cells other than the cholinergic motor neurons. One example is the effect of RHO-1(G14V) expression on the defecation cycle. Wild type animals defecate by initiating a series of three muscle contractions; (posterior body-wall-muscle contraction (pBoc), anterior body-wall-muscle contraction (aBoc) and enteric-muscle contraction (Emc)), regularly with an interval between cycles of 50sec [29]. Although the aBoc and Emc steps of this cycle require neuronal activity via a GABAergic motor neuron the pBoc step and initiation of the defecation cycle do not require neuronal input [45]. Expression of constitutively active hsRHO-1(G14V), but not nRHO-1(G14V) resulted in an almost complete block in initiation of the defecation cycle (as defined by the interval between pBoc) (Figure 4), however, when a cycle did occur all three motor steps (pBoc, aBoc and Emc) were observed. This suggests that RHO-1 acts in non-cholinergic cells to regulate defecation cycle initiation rather than muscle contractions themselves. Inhibition of endogenous RHO-1 in adults using hsC3 transferase also resulted in a defect in the defecation motor programme. Although the cycle was not completely blocked, as it was by overexpression of hsRHO-1(G14V), it became very variable and a slight increase in the average cycle period was observed (Figure 4).

Bottom Line: Changes in RHO-1 signaling in cholinergic neurons affected locomotion, pharyngeal pumping and fecundity.Changes in RHO-1 signaling outside the cholinergic neurons resulted in defective defecation, ovulation, and changes in C. elegans body morphology.Finally both increased and decreased RHO-1 signaling in adults resulted in death within hours.

View Article: PubMed Central - PubMed

Affiliation: MRC Cell Biology Unit, MRC Laboratory for Molecular Cell Biology and Department of Neuroscience, Physiology and Pharmacology, University College, London, United Kingdom.

ABSTRACT
The Rho family of small GTPases are essential during early embryonic development making it difficult to study their functions in adult animals. Using inducible transgenes expressing either a constitutively active version of the single C. elegans Rho ortholog, RHO-1, or an inhibitor of endogenous Rho (C3 transferase), we demonstrate multiple defects caused by altering Rho signaling in adult C. elegans. Changes in RHO-1 signaling in cholinergic neurons affected locomotion, pharyngeal pumping and fecundity. Changes in RHO-1 signaling outside the cholinergic neurons resulted in defective defecation, ovulation, and changes in C. elegans body morphology. Finally both increased and decreased RHO-1 signaling in adults resulted in death within hours. The multiple post-developmental roles for Rho in C. elegans demonstrate that RhoA signaling pathways continue to be used post-developmentally and the resulting phenotypes provide an opportunity to further study post-developmental Rho signaling pathways using genetic screens.

Show MeSH
Related in: MedlinePlus