Mammalian Metallothionein Is Functional in Yeast

Thiele, Dennis J.; Walling, M. J.; Hamer, Dean H.

doi:10.1126/science.3080806

Cited by 76 publications

(36 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We also showed that the lethality induced by a ySAG deletion could be fully complemented by human SAG, indicating conservation of function. Two RING motif-disrupted mutants, G1 factor needed for normal G1 phase 2.5 2.4 3.6 G1 regulation YGR129W (SYF2) Synthetic lethal with Cdc40 2.6 2.3 2.9 S/G2 control (Boger Nadjar et al, 1998) YGR188C (BUB1) Ser/thr protein kinase 2.0 2.0 2.2 G2/M checkpoint control (Farr and Hoyt, 1998) YJL030W (MAD2) Spindle-assembly checkpoint protein 2.5 2.8 3.5 Mitosis (Li and Benezra, 1996) (Thiele et al, 1986). In budding yeast, it is known that there is only one member of the ySAG/yROC/yRbx/Hrt family.…”

Section: Discussionmentioning

confidence: 99%

Yeast homolog of human SAG/ROC2/Rbx2/Hrt2 is essential for cell growth, but not for germination: chip profiling implicates its role in cell cycle regulation

Swaroop¹,

Wang²,

Miller³

et al. 2000

Oncogene

View full text Add to dashboard Cite

In an attempt to understand the signaling pathway mediating redox-induced apoptosis, we cloned SAG, an evolutionarily conserved zinc RING ®nger gene that, when overexpressed, protects cells from apoptosis induced by redox agents. Here we report functional characterization of SAG by the use of yeast genetics approach. Targeted disruption of ySAG, yeast homolog of human SAG, and subsequent tetrad analysis revealed that ySAG is required for yeast viability. Complementation experiment showed that the lethal phenotype induced by the ySAG deletion is fully rescued by wildtype SAG, but not by several hSAG mutants. Complementation experiment has also con®rmed that ySAG is essential for normal vegetative growth, rather than being required for sporulation. Furthermore, cell death induced by SAG deletion was accompanied by cell enlargement and abnormal cell cycle pro®ling with an increased DNA content. Importantly, SAG was found to be the second family member of Rbx (RING box protein) or ROC (Regulator of cullins) or Hrt that is a component of SCF E3 ubiquitin ligase. Indeed, like ROC1/Rbx1/Hrt1, SAG binds to Cul1 and SAG-Cul1 complex has ubiquitin ligase activity to promote poly-ubiquitination of E2/ Cdc34. This ligase activity is required for complementation of death phenotype induced by ySAG disruption. Finally, chip pro®ling of the entire yeast genome revealed induction of several G1/S as well as G2/M checkpoint control genes upon SAG withdrawal. Thus, SAG appears to control cell cycle progression in yeast by promoting ubiquitination and degradation of cell cycle regulatory proteins.

show abstract

Section: Discussionmentioning

confidence: 99%

Yeast homolog of human SAG/ROC2/Rbx2/Hrt2 is essential for cell growth, but not for germination: chip profiling implicates its role in cell cycle regulation

Swaroop¹,

Wang²,

Miller³

et al. 2000

Oncogene

View full text Add to dashboard Cite

show abstract

“…For RNA blot analysis, 20 ,ug of each RNA sample was fractionated on a 1.5% agarose-formaldehyde gel, transferred to nitrocellulose, and hybridized with 32P-labeled probes (31). To detect CUP) gene-specific mRNA, a nick-translated CUP) XbaIKpnI DNA restriction fragment was used (41). ACE] mRNA was detected by using a nick-translated 1.8-kb HindIII DNA fragment purified from plasmid p2g by agarose gel electrophoresis.…”

Section: Methodsmentioning

confidence: 99%

A cysteine-rich nuclear protein activates yeast metallothionein gene transcription.

Szczypka¹,

Thiele²

1989

Mol. Cell. Biol.

View full text Add to dashboard Cite

The ACE1 gene of the yeast Saccharomyces cerevisiae is required for copper-inducible transcription of the metallothionein gene (CUP1). The sequence of the cloned ACE1 gene predicted an open reading frame for translation of a 225-amino-acid polypeptide. This polypeptide was characterized by an amino-terminal half rich in cysteine residues and positively charged amino acids. The arrangement of many of the 12 cysteines in the configuration Cys-X-Cys or Cys-X-X-Cys suggested that the ACE1 protein may bind metal ions. The carboxyl-terminal half of the ACE1 protein was devoid of cysteines but was highly acidic in nature. The ability of a bifunctional ACE1-beta-galactosidase fusion protein to accumulate in yeast cell nuclei was consistent with the possibility that ACE1 plays a direct role in the regulation of copper-inducible transcription of the yeast metallothionein gene.

show abstract

“…One such mechanism proposes the involvement of metallothioneins (MTs), which are intracellular cytoplasmic proteins containing high amounts of thiol groups as well as being rich in cysteine. These thiol groups are able to bind to several cytotoxic agents containing heavy metals (Thiele et al, 1986), such as cisplatinum. MTs appear to have a physiological role in the absorption, transport and metabolism of important trace metals, as well as a role in heavy metal detoxification.…”

mentioning

confidence: 99%

P-glycoprotein and metallothionein expression and resistance to chemotherapy in osteosarcoma

Shnyder¹,

Hayes²,

Pringle³

et al. 1998

Br J Cancer

View full text Add to dashboard Cite

Summary The expression of the drug resistance (DR) mediators P-glycoprotein (P-gp) and the metallothioneins (MT) was assessed immunohistochemically in biopsy material from patients with high-grade malignant osteosarcoma (OS). No significant difference was found in survival rate between expressors of both P-gp and MT and non-expressors. Thus, it was concluded that lack of expression of these two drug resistance-related proteins does not appear to confer any advantage in terms of patient survival in osteosarcoma.Keywords: osteosarcoma; P-glycoprotein; metallothioneins; drug resistance; immunohistochemistry; confocal laser scanning microscopy Failure to respond to, or relapse from, drug therapy are among the most common causes of death in patients with osteosarcoma (OS). Tumour unresponsiveness to drug therapy may be related to many factors. The most frequently described model of drug resistance is the P-glycoprotein (P-gp)-specific multiple-drug resistance (MDR) gene phenotype (Juliano and Ling, 1976). Increased levels of P-gp are thought to confer MDR to tumour cells by decreasing the net intracellular accumulation of unrelated lipophilic cytotoxic agents, such as doxorubicin and vincristine (Weinstein et al, 1990), which are commonly used in treatment regimens for high-grade malignant OS. Results from earlier studies carried out on OS have been conflicting. While some have shown a correlation between Pgp expression at biopsy, and response to therapy (Chan et al, 1991; Wunder et al, 1993), other groups have shown that it is possible for OS cells to be P-gp negative, but still be drug resistant (Shnyder et al, 1994;Kandel et al, 1995).Various mechanisms for drug resistance due to the exclusion from cells of cisplatinum, which is also commonly used in therapy for OS, have also been proposed (Richon et al, 1987;Andrews and Howell, 1990). One such mechanism proposes the involvement of metallothioneins (MTs), which are intracellular cytoplasmic proteins containing high amounts of thiol groups as well as being rich in cysteine. These thiol groups are able to bind to several cytotoxic agents containing heavy metals (Thiele et al, 1986), such as cisplatinum. MTs appear to have a physiological role in the absorption, transport and metabolism of important trace metals, as well as a role in heavy metal detoxification. MTs have also been shown to affect the cellular sensitivity to cisplatinum (Bahnson et al, 1991; Kasahara et al, 1991;Chin et al, 1993;Kondo et al, 1995). No previous studies have reported on MT expression in OS.In this study, the expression of P-gp and MT was assessed immunohistochemically in biopsy material from patients with clinically diagnosed high-grade malignant OS, and the expression Received 29 May 1996 Revised 27 January 1998 Accepted 10 February 1998Correspondence to: SD Shnyder, Department of Biochemistry, University of Otago, Box 56, Dunedin, New Zealand of these molecules was statistically analysed with respect to patient survival data (over 5 years) to determine whether there were any correla...

show abstract

Mammalian Metallothionein Is Functional in Yeast

Cited by 76 publications

References 7 publications

Yeast homolog of human SAG/ROC2/Rbx2/Hrt2 is essential for cell growth, but not for germination: chip profiling implicates its role in cell cycle regulation

Yeast homolog of human SAG/ROC2/Rbx2/Hrt2 is essential for cell growth, but not for germination: chip profiling implicates its role in cell cycle regulation

A cysteine-rich nuclear protein activates yeast metallothionein gene transcription.

P-glycoprotein and metallothionein expression and resistance to chemotherapy in osteosarcoma

Contact Info

Product

Resources

About