ApiLoc - A database of published protein sub-cellular localisation in Apicomplexa

version 3 (curated until May 28, 2011)

The plastid of Toxoplasma gondii is divided by association with the centrosomes.

Striepen, B., Crawford, M. J., Shaw, M. K., Tilney, L. G., Seeber, F., Roos, D. S. (2000 Dec 25, J Cell Biol)

Apicomplexan parasites harbor a single nonphotosynthetic plastid, the apicoplast, which is essential for parasite survival. Exploiting Toxoplasma gondii as an accessible system for cell biological analysis and molecular genetic manipulation, we have studied how these parasites ensure that the plastid and its 35-kb circular genome are faithfully segregated during cell division. Parasite organelles were labeled by recombinant expression of fluorescent proteins targeted to the plastid and the nucleus, and time-lapse video microscopy was used to image labeled organelles throughout the cell cycle. Apicoplast division is tightly associated with nuclear and cell division and is characterized by an elongated, dumbbell-shaped intermediate. The plastid genome is divided early in this process, associating with the ends of the elongated organelle. A centrin-specific antibody demonstrates that the ends of dividing apicoplast are closely linked to the centrosomes. Treatment with dinitroaniline herbicides (which disrupt microtubule organization) leads to the formation of multiple spindles and large reticulate plastids studded with centrosomes. The mitotic spindle and the pellicle of the forming daughter cells appear to generate the force required for apicoplast division in Toxoplasma gondii. These observations are discussed in the context of autonomous and FtsZ-dependent division of plastids in plants and algae.

PubMed: 11134072, full text

Localisation information

TGME49_116400 (alpha tubulin, TUBA1) tubulin alpha chain

Experimental localisation: inner membrane complex during tachyzoite schizont
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "The inner membrane complex of developing daughter parasites was visualized 24 h after infection either by staining of fixed and permeabilized parasites with monoclonal antiヨNET1 and rhodamine-conjugated rabbit antiヨmouse immunoglobulin (AヨF, red), or in living parasites transiently transfected with ptubYFPヨa-tubulin (GヨL, green);"
  • Microscopy type: Light, EM
  • Microscopy method: YFP tag
  • Strain: RH
  • Gene model mapping comments: Blast from M20024.1, annotation matches
  • Localisation record: inner membrane complex during tachyzoite schizont

TGME49_066960 (beta tubulin) tubulin beta chain

Experimental localisation: inner membrane complex microtubules during tachyzoite, apical during tachyzoite, nucleus during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "Both NH2- and COOH-terminal fusions of YFP with b-tubulin showed general cytoplasmic staining without incorporation into any specific structure, presumably due to steric limitations imposed by the incorporation of a bulky GFP tag into microtubules (data not shown). In contrast, YFP-a-tubulin labeled the subpellicular microtubules of both the mother and developing daughter parasites (Fig 5G and Fig J). We also observed a spot of intense staining at the very apical end of the parasite (Fig 5 J, arrowhead), probably attributable to either the conoid or the apical polar rings (Nichols and Chiappino 1987 ; Morrissette et al. 1997 ). An additional focus of intense labeling in developing daughter parasites was observed in the nuclear region (Fig 5 G, double arrow). Double labeling with centrosome- and microtubule-specific antibodies (not shown) reveal that this label represents ends of the intranuclear mitotic spindle. "
  • Microscopy type: Light
  • Microscopy method: YFP tag, GFP tag
  • Strain: RH
  • Gene model mapping comments: Blast from M20025, annotation matches
  • Localisation record: inner membrane complex microtubules and apical and nucleus during tachyzoite

TGME49_064080 (ACP) acyl carrier protein

Experimental localisation: apicoplast during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "Parasites were transfected with construct ptubACP-GFP before infection of coverslip cultures and imaged 24 h after electroporation. A single oval apicoplast is observed just apical to the nucleus in most parasites "
  • Microscopy type: Light
  • Microscopy method: GFP tag
  • Strain: RH
  • Gene model mapping comments: inferred from another publication
  • Localisation record: apicoplast during tachyzoite

TGME49_047460 (pCNA, PCNA1) proliferating cell nuclear antigen 1

Experimental localisation: nucleus during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "To more precisely characterize the timing and context of plastid division, we labeled both the nucleus and plastid in living parasites, taking advantage of a proliferating cell nuclear antigen 1 (PCNA)ヨGFP fusion protein to label the T. gondii nucleus (Guerini et al. 2000 ). "
  • Microscopy type: Light
  • Microscopy method: GFP tag
  • Strain: RH
  • Gene model mapping comments: Blast from AF242301.1, annotation matches
  • Localisation record: nucleus during tachyzoite

TGME49_098990 (FNR) ferredoxin NADP+ oxidoreductase, putative

Experimental localisation: apicoplast during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "For these experiments, the plastid was labeled using a RFP reporter (a native fluorescent molecule that is entirely distinct from GFP; Matz et al. 1999 ) fused to Ferredoxin/NADPH Reductase (FNR; Vollmer et al. 2000 ). "
  • Microscopy type: Light
  • Microscopy method: RFP tag
  • Strain: RH
  • Gene model mapping comments: Blast from AJ242627.1, annotation matches
  • Localisation record: apicoplast during tachyzoite

TGME49_031640 (IMC1, ALV1, IMC, NET1) membrane skeletal protein IMC1

Experimental localisation: inner membrane complex during tachyzoite schizont
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "The inner membrane complex of developing daughter parasites was visualized 24 h after infection either by staining of fixed and permeabilized parasites with monoclonal antiヨ NET1 and rhodamine-conjugated rabbit antiヨmouse immunoglobulin (AヨF, red),"
  • Microscopy type: Light
  • Microscopy method: monoclonal antibody
  • Strain: RH
  • Gene model mapping comments: inferred from another publication
  • Localisation record: inner membrane complex during tachyzoite schizont

TGME49_047230 (centrin) caltractin (centrin), putative

Experimental localisation: centrosome
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "Double labeling with anticentrin antibody reveals the presence of multiple centrosomes, closely associated with the reticulate apicoplast (Fig. 6, C and E)."
  • Microscopy type: Light, EM
  • Microscopy method: polyclonal antibody directly to protein
  • Strain: RH
  • Gene model mapping comments: inferred from another publication
  • Localisation record: centrosome