title: The C. elegans NR4A nuclear receptor gene nhr-6 promotes cell cycle progression in the spermatheca lineage.
abstract: BACKGROUND
  NR4A nuclear receptors are a conserved, functionally diverse group of nuclear receptors that regulate multiple cellular processes including proliferation and differentiation. The gene nhr-6 encodes the sole Caenorhabditis elegans NR4A nuclear receptor homolog with an essential role in reproduction by regulating morphogenesis of the spermatheca, a somatic gonad organ involved in ovulation and fertilization.
  
  
  RESULTS
  Here, we identify the spermatheca cell lineage defects that occur in nhr-6 mutants. Utilizing cell marker analysis, we find that nhr-6 is required for cell cycle progression and that the cell proliferation phenotype is not due to premature cell cycle exit. We also show that loss of the negative cell cycle regulators fzr-1 and lin-35 suppresses the cell proliferation defects. We further demonstrate that NHR-6 activity intersects with Eph receptor signaling during spermatheca cell proliferation.
  
  
  CONCLUSIONS
  NHR-6 has an essential function in promoting cell cycle progression during G1 phase in a specific spermatheca cell lineage. Genetic suppression of the proliferation phenotype does not affect the differentiation phenotypes observed in nhr-6 mutants, indicating a dualistic role for nhr-6 in regulating cell proliferation and cell differentiation during spermatheca organogenesis.
authors.affiliation: Department of Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, Monroe, Louisiana.
authors.forename: Brandon
authors.initials: B
authors.lastname: Praslicka
authors.forename: Chris R
authors.initials: CR
authors.lastname: Gissendanner
mesh_terms: D000825:Animal Structures / Q000196:embryology*; D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000235:genetics; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D016193:G1 Phase / Q000502:physiology*; D038081:Organogenesis / Q000502:physiology*; D036082:Receptor, EphA1 / Q000235:genetics / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*
chemical_list: D029742:Caenorhabditis elegans Proteins; C526782:Nhr-6 protein, C elegans; D018160:Receptors, Cytoplasmic and Nuclear; D036082:Receptor, EphA1
keywords: Eph receptor; G1/S; GFP; fzr-1; lin-35; rnr; somatic gonad; vab-1; vab-2