Metabolic pathways for differentiation-inducing factor-1 and their regulation are conserved between closely related Dictyostelium species, but not between distant members of the family.
There is suggestive evidence that a conserved signalling system involving differentiation inducing factor-1 (DIF-1) controls stalk cell differentiation in a variety of slime mould species. In the standard laboratory species, Dictyostelium discoideum, DIF-1 is first inactivated by dechlorination catalysed by DIF-1 dechlorinase, then by several hydroxylation events, so that eventually about 12 metabolites are produced. If DIF-1 is used as a signal molecule in other species, they too must be able to metabolize it. We report here that the essentials of DIF-1 metabolism are conserved in D. mucoroides, the closest relative of D. discoideum. Both the dechlorinase and hydroxylase enzymes were present in D. mucoroides, and living cells of both species produced a similar spectrum of metabolites from [3H]DIF-1. Furthermore, DIF-1 dechlorinase was induced by DIF-1, as in D. discoideum, and this induction was repressed by ammonia and cAMP. DIF-1 dechlorinase could not be detected in cell extracts from D. minutum or Polysphondylium violaceum. However, living cells of both species are able to metabolize DIF-1; P. violaceum seems to produce a small amount of the monodechlorinated compound, DIF-3, but all other metabolites from both species appear to be unique. Thus all investigated species can metabolize DIF-1, but the exact route of metabolism is not highly conserved.
van Es
S
S
Cell Biology Unit, University of Leiden, The Netherlands.
Hodgkinson
S
S
Schaap
P
P
Kay
R R
RR
D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D004023:Dictyostelium / Q000166:cytology* / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D004790:Enzyme Induction / Q000235:genetics; D006588:Hexanones / Q000378:metabolism*; D013045:Species Specificity
D006588:Hexanones; C053433:1-((3,5-dichloro)-2,6-dihydroxy-4-methoxyphenyl)-1-hexanone