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

version 3 (curated until May 28, 2011)

In vivo expression and distribution of dense granule protein 7 (GRA7) in the exoenteric (tachyzoite, bradyzoite) and enteric (coccidian) forms of Toxoplasma gondii.

Ferguson, D. J., Jacobs, D., Saman, E., Dubremetz, J. F., Wright, S. E. (1999 Sep, Parasitology)

The in vivo expression and distribution of the dense granule protein GRA7 was examined in both the exoenteric (tachyzoite and bradyzoite) and enteric (coccidian) forms of Toxoplasma gondii by immunocytochemistry. There was strong staining of GRA7 in granules within all the infectious stages (tachyzoite, bradyzoite, merozoite and sporozoite). During tachyzoite development, GRA7 was secreted and was associated with the parasitophorous vacuole. In contrast, although there was staining of granules within the bradyzoites of more mature cysts, there appeared to be little staining of the tissue cyst wall or host cell. The apparent stage-specific variation in secretion of GRA7 between tachyzoites and bradyzoites was confirmed by double labelling using stage-specific markers (SAG1 and BAG1). In the enteric forms in the cat gut there was strong labelling of the PV containing early asexual and sexual stages and staining of a few granules in the apical cytoplasm of the merozoite. The positive enteric staining pattern differentiates GRA7 from the other GRA proteins (GRA1-6) which were absent in the merozoites and enteric stages. The staining pattern of GRA7 with strong staining during tachyzoite and enteric development and reduced staining in the tissue cysts is similar to that seen for NTPases. The function of GRA7 is unknown but it is unique among the dense granule proteins in being expressed in all the infectious forms of T. gondii which would point to a basic role in the vacuolar adaptations required for active parasite development.

PubMed: 10503251, full text

Localisation information

TGME49_003310 (GRA7) dense granule protein 7

Experimental localisation: dense granule during tachyzoite, dense granule during bradyzoite, dense granule during merozoite, dense granule during sporozoite, parasitophorous vacuole during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "There was strong staining of GRA7 in granules within all the infectious stages (tachyzoite, bradyzoite, merozoite and sporozoite). During tachyzoite development, GRA7 was secreted and was associated with the parasitophorous vacuole. In contrast, although there was staining of granules within the bradyzoites of more mature cysts, there appeared to be little staining of the tissue cyst wall or host cell."
  • Microscopy type: Light
  • Microscopy method: Monoclonal antibody directly to protein
  • Strain: M3, RRA
  • Gene model mapping comments: inferred from another publication
  • Localisation record: dense granule during tachyzoite and bradyzoite and merozoite and sporozoite, PV during tachyzoite

TGME49_077240 (NTPase, NTP1) nucleoside-triphosphatase I

Experimental localisation: dense granule during merozoite, parasitophorous vacuole during merozoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "Using double labelling, it could be shown that GRA7 co-localized with the NTPase in both the PV and merozoite cytoplasm (Fig. 1 M)."
  • Microscopy type: Light
  • Microscopy method: polyclonal antibody directly to protein
  • Strain: M3, RRA
  • Gene model mapping comments: inferred from another publication
  • Localisation record: dense granule and PV during merozoite

TGME49_110780 (GRA4) hypothetical protein

Experimental localisation: dense granule during sporozoite, not rhoptry during sporozoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "In double labelled sporozoites, there appeared to be co-localization of GRA7 and GRA4 (Fig. 1 O) but not with a rhoptry protein (Fig. 1 P) confirming the dense granule location of GRA7."
  • Microscopy type: Light
  • Microscopy method: polyclonal antibody directly to protein
  • Strain: M3, RRA
  • Gene model mapping comments: inferred from another publication
  • Localisation record: dense granule and not rhoptry during sporozoite