<i>Toxoplasma gondii</i>
            Requires Glycogen Phosphorylase for Balancing Amylopectin Storage and for Efficient Production of Brain Cysts

Sugi, Tatsuki; Tu, Vincent; Ma, Yanfen; Tomita, Tadakimi; Weiss, Louis M.

doi:10.1128/mbio.01289-17

Cited by 54 publications

(64 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Tachyzoite-to-bradyzoite differentiation is linked with major changes in carbohydrate and polysaccharide metabolism (38,48,49). The Toxoplasma cyst wall is recognized by a variety of lectins, including concanavalin A (␣-D-mannose or ␣-D-glucose), FIG 5 s-WGA colocalizes with GRA6 at the cyst periphery, and s-WGA accumulation at the cyst periphery is GRA2 independent in mature cysts.…”

Section: Discussionmentioning

confidence: 99%

Succinylated Wheat Germ Agglutinin Colocalizes with the Toxoplasma gondii Cyst Wall Glycoprotein CST1

Guevara

Fox

Bzik

2020

mSphere

View full text Add to dashboard Cite

The glycosylated mucin domain of the Toxoplasma gondii cyst wall glycoprotein CST1 is heavily stained by Dolichos biflorus agglutinin, a lectin that binds to N-acetylgalactosamine. The cyst wall is also heavily stained by the chitin binding lectin succinylated wheat germ agglutinin (s-WGA), which selectively binds to N-acetylglucosamine-decorated structures. Here, we tracked the localization of N-acetylglucosamine-decorated structures that bind to s-WGA in immature and mature in vitro cysts. s-WGA localization was observed at the cyst periphery 6 h after the differentiation of the tachyzoite-stage parasitophorous vacuole. By day 1 and at all later times after differentiation, s-WGA was localized in a continuous staining pattern at the cyst wall. Coinciding with the maturation of the cyst matrix by day 3 of cyst development, s-WGA also localized in a continuous matrix pattern inside the cyst. s-WGA localized in both the outer and inner layer regions of the cyst wall and in a continuous matrix pattern inside mature 7-and 10-day-old cysts. In addition, s-WGA colocalized in the cyst wall with CST1, suggesting that N-acetylglucosamineand N-acetylgalactosamine-decorated molecules colocalized in the cyst wall. In contrast to CST1, GRA4, and GRA6, the relative accumulation of the molecules that bind s-WGA in the cyst wall was not dependent on the expression of GRA2. Our results suggest that GRA2-dependent and GRA2-independent mechanisms regulate the trafficking and accumulation of glycosylated molecules that colocalize in the cyst wall. IMPORTANCE Chronic Toxoplasma gondii infection is maintained in the central nervous system by thick-walled cysts. If host immunity wanes, cysts recrudesce and cause severe and often lethal toxoplasmic encephalitis. Currently, there are no therapies to eliminate cysts, and little biological information is available regarding cyst structure(s). Here, we investigated cyst wall molecules recognized by succinylated wheat germ agglutinin (s-WGA), a lectin that specifically binds to N-acetylglucosamine-decorated structures. N-Acetylglucosamine regulates cell signaling and plays structural roles at the cell surface in many organisms. The cyst wall and cyst matrix were heavily stained by s-WGA in mature cysts and were differentially stained during cyst development. The relative accumulation of molecules that bind to s-WGA in the cyst wall was not dependent on the expression of GRA2. Our findings suggest that glycosylated cyst wall molecules gain access to the cyst wall via GRA2-dependent and GRA2-independent mechanisms and colocalize in the cyst wall.

show abstract

Section: Discussionmentioning

confidence: 99%

Succinylated Wheat Germ Agglutinin Colocalizes with the Toxoplasma gondii Cyst Wall Glycoprotein CST1

Guevara

Fox

Bzik

2020

mSphere

View full text Add to dashboard Cite

show abstract

“…The parasitophorous vacuole Toxoplasma replicates within is modified into a heavily glycosylated cyst wall, containing many stage-specific proteins of unknown function (Coppin et al, 2005;Ferguson, 2004;Tomita et al, 2013Tomita et al, , 2017Tu et al, 2019). Parasite metabolism also changes drastically during differentiation, relying on anaerobic glycolysis instead of aerobic respiration and accumulating cytoplasmic starch granules (Denton et al, 1996;Gué rardel et al, 2005;Sugi et al, 2017). Underpinning these dramatic changes in lifestyle, studies have identified hundreds to thousands of genes as differentially regulated between tachyzoites and bradyzoites (Behnke et al, 2008;Buchholz et al, 2011;Cleary et al, 2002;Manger et al, 1998;Pittman et al, 2014;Radke et al, 2005;Yahiaoui et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Identification of a Master Regulator of Differentiation in Toxoplasma

Waldman

Schwarz

Wadsworth

et al. 2020

Cell

187

267

View full text Add to dashboard Cite

Graphical AbstractHighlights d BFD1 is a master regulator of chronic-stage differentiation in Toxoplasma gondii d DBFD1 parasites fail to differentiate in cell culture or form cysts in infected mice d Conditional expression of BFD1 is sufficient to induce differentiation d BFD1 binds transcriptional start sites of genes induced during chronic stages SUMMARY Toxoplasma gondii chronically infects a quarter of the world's population, and its recrudescence can cause life-threatening disease in immunocompromised individuals and recurrent ocular lesions in the immunocompetent. Acute-stage tachyzoites differentiate into chronic-stage bradyzoites, which form intracellular cysts resistant to immune clearance and existing therapies. The molecular basis of this differentiation is unknown, despite being efficiently triggered by stresses in culture. Through Cas9-mediated screening and single-cell profiling, we identify a Myb-like transcription factor (BFD1) necessary for differentiation in cell culture and in mice. BFD1 accumulates during stress and its synthetic expression is sufficient to drive differentiation. Consistent with its function as a transcription factor, BFD1 binds the promoters of many stage-specific genes and represents a counterpoint to the ApiAP2 factors that dominate our current view of parasite gene regulation. BFD1 provides a genetic switch to study and control Toxoplasma differentiation and will inform prevention and treatment of chronic infections.

show abstract

“…The parasitophorous vacuole that Toxoplasma replicates within is modified into a heavily glycosylated cyst wall, containing many stage-specific proteins of unknown function Ferguson, 2004;Tomita et al, 2013;. Parasite metabolism changes drastically, relying on anaerobic glycolysis instead of aerobic respiration and accumulating cytoplasmic starch granules (Denton et al, 1996;Guérardel et al, 2005;Sugi et al, 2017). Underpinning these dramatic changes in lifestyle, different studies have found hundred to thousands of genes are differentially regulated between tachyzoites and bradyzoites derived in vitro or in vivo (Behnke et al, 2008;Buchholz et al, 2011;Cleary et al, 2002;Lescault et al, 2010;Manger et al, 1998;Naguleswaran et al, 2010;Pittman et al, 2014;Radke et al, 2005;Ramakrishnan et al, 2019;Yahiaoui et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Identification of a master regulator of differentiation inToxoplasma

Waldman

Schwarz

Wadsworth

et al. 2019

Preprint

View full text Add to dashboard Cite

Toxoplasma gondii chronically infects a quarter of the world's population, and its recrudescence can cause life-threatening disease in immunocompromised individuals and recurrent ocular lesions in the immunocompetent. Chronic stages are established by differentiation of rapidly replicating tachyzoites into slow-growing bradyzoites, which form intracellular cysts resistant to immune clearance and existing therapies. Despite its central role in infection, the molecular basis of chronic differentiation is not understood. Through Cas9-mediated genetic screening and single-cell transcriptional profiling, we identify and characterize a putative transcription factor (BFD1) as necessary and sufficient for differentiation. Translation of BFD1 appears to be stress regulated, and its constitutive expression elicits differentiation in the absence of stress. As a Myb-like factor, BFD1 provides a counterpoint to the ApiAP2 factors which dominate our current view of parasite gene regulation. Overall, BFD1 provides a genetic switch to study and control Toxoplasma differentiation, and will inform prevention and treatment of chronic infection.

show abstract

Toxoplasma gondii Requires Glycogen Phosphorylase for Balancing Amylopectin Storage and for Efficient Production of Brain Cysts

Cited by 54 publications

References 32 publications

Succinylated Wheat Germ Agglutinin Colocalizes with the Toxoplasma gondii Cyst Wall Glycoprotein CST1

Succinylated Wheat Germ Agglutinin Colocalizes with the Toxoplasma gondii Cyst Wall Glycoprotein CST1

Identification of a Master Regulator of Differentiation in Toxoplasma

Identification of a master regulator of differentiation inToxoplasma

Contact Info

Product

Resources

About