Chunyan Liao - Academia.edu (original) (raw)

Papers by Chunyan Liao

Current Microbiology, 2005

Several Cry1Ac binding proteins from midgut of Helicoverpa armigera were purified using toxin-aff... more Several Cry1Ac binding proteins from midgut of Helicoverpa armigera were purified using toxin-affinity chromatography. Enzyme assays showed that the purified proteins had strong aminopeptidase activity. The N-terminal sequences confidently identified a 124-kDa binding protein as an aminopeptidase N (APN), and some similarity suggests that a 162-kDa binding protein may also be an APN. Two minor binding proteins were not characterized.

Journal of Invertebrate Pathology, 2002

The susceptibilities of the major pests of cotton in Australia, Helicoverpa armigera and Helicove... more The susceptibilities of the major pests of cotton in Australia, Helicoverpa armigera and Helicoverpa punctigera, to some insecticidal proteins from Bacillus thuringiensis were tested by bioassay. A commercial formulation, DiPel, and individual purified insecticidal proteins were tested. H. armigera was consistently more tolerant to B. thuringiensis insecticidal proteins than was H. punctigera, although both were susceptible to only a limited range of these proteins. Only Cry1Ab, Cry1Ac, Cry2Aa, Cry2Ab, and Vip3A killed H. armigera at dosages that could be considered acceptable. There was no significant difference in the toxicities of Cry1Fa and Cry1Ac for H. punctigera but Cry1Fa had little toxicity for H. armigera. The five instars of H. armigera did not differ significantly in their susceptibility to DiPel on the basis of LC50. However, there were significant differences in the susceptibility to Cry1Ac and Cry2Aa of three strains of H. armigera. Bioassays conducted with Cry1Ac and Cry2Aa showed that there was a small but significant negative interaction between these δ-endotoxins.

Journal of Invertebrate Pathology, 2002

The susceptibilities of the major pests of cotton in Australia, Helicoverpa armigera and Helicove... more The susceptibilities of the major pests of cotton in Australia, Helicoverpa armigera and Helicoverpa punctigera, to some insecticidal proteins from Bacillus thuringiensis were tested by bioassay. A commercial formulation, DiPel, and individual purified insecticidal proteins were tested. H. armigera was consistently more tolerant to B. thuringiensis insecticidal proteins than was H. punctigera, although both were susceptible to only a limited range of these proteins. Only Cry1Ab, Cry1Ac, Cry2Aa, Cry2Ab, and Vip3A killed H. armigera at dosages that could be considered acceptable. There was no significant difference in the toxicities of Cry1Fa and Cry1Ac for H. punctigera but Cry1Fa had little toxicity for H. armigera. The five instars of H. armigera did not differ significantly in their susceptibility to DiPel on the basis of LC(50). However, there were significant differences in the susceptibility to Cry1Ac and Cry2Aa of three strains of H. armigera. Bioassays conducted with Cry1Ac and Cry2Aa showed that there was a small but significant negative interaction between these delta-endotoxins.

Current Microbiology, 2005

Several Cry1Ac binding proteins from midgut of Helicoverpa armigera were purified using toxin-aff... more Several Cry1Ac binding proteins from midgut of Helicoverpa armigera were purified using toxin-affinity chromatography. Enzyme assays showed that the purified proteins had strong aminopeptidase activity. The N-terminal sequences confidently identified a 124-kDa binding protein as an aminopeptidase N (APN), and some similarity suggests that a 162-kDa binding protein may also be an APN. Two minor binding proteins were not characterized.

Molecular microbiology, 2005

We demonstrate a role for Qri2 in the essential DNA repair function of the Smc5/6 complex in Sacc... more We demonstrate a role for Qri2 in the essential DNA repair function of the Smc5/6 complex in Saccharomyces cerevisiae . We generated temperaturesensitive ( ts ) mutants in QRI2 and characterized their properties. The mutants arrest after S phase and prior to mitosis. Furthermore, the arrest is dependant on the Rad24 checkpoint, and is also accompanied by phosphorylation of the Rad53 checkpoint effector kinase. The mutants also display genome instability and are sensitive to agents that damage DNA. Twohybrid screens reveal a physical interaction between Qri2 and proteins that are non-Smc elements of the Smc5/6 DNA repair complex, which is why we propose the name NSE4 for the open reading frame previously known as QRI2 . A key role for Nse4 in Smc5/ 6 function is likely, as overexpressing known subunits of the Smc5/6 complex suppresses nse4 ts cell cycle arrest. The nse4 ts growth arrest is non-lethal and unlike the catastrophic nuclear fragmentation phenotype of smc6 ts mutants, the nucleus remains intact; replicative intermediates and sheared DNA are not detected. This could imply a role for Nse4 in maintenance of higher order chromosome structure.

PLOS One, 2010

Background: Automated standoff detection and classification of explosives based on their characte... more Background: Automated standoff detection and classification of explosives based on their characteristic vapours would be highly desirable. Biologically derived odorant receptors have potential as the explosive recognition element in novel biosensors. Caenorhabditis elegans' genome contains over 1,000 uncharacterised candidate chemosensory receptors. It was not known whether any of these respond to volatile chemicals derived from or associated with explosives.

PloS one, 2014

Ionizing radiation (IR) is a common therapeutic agent in cancer therapy. It damages normal tissue... more Ionizing radiation (IR) is a common therapeutic agent in cancer therapy. It damages normal tissue and causes side effects including dermatitis and mucositis. Here we use the feather follicle as a model to investigate the mechanism of IR-induced tissue damage, because any perturbation of feather growth will be clearly recorded in its regular yet complex morphology. We find that IR induces defects in feather formation in a dose-dependent manner. No abnormality was observed at 5 Gy. A transient, reversible perturbation of feather growth was induced at 10 Gy, leading to defects in the feather structure. This perturbation became irreversible at 20 Gy. Molecular and cellular analysis revealed P53 activation, DNA damage and repair, cell cycle arrest and apoptosis in the pathobiology. IR also induces patterning defects in feather formation, with disrupted branching morphogenesis. This perturbation is mediated by cytokine production and Stat1 activation, as manipulation of cytokine levels or ectopic Stat1 over-expression also led to irregular feather branching. Furthermore, AG-490, a chemical inhibitor of Stat1 signaling, can partially rescue IR-induced tissue damage. Our results suggest that the feather follicle could serve as a useful model to address the in vivo impact of the many mechanisms of IR-induced tissue damage.

PLoS ONE, 2010

Background: Automated standoff detection and classification of explosives based on their characte... more Background: Automated standoff detection and classification of explosives based on their characteristic vapours would be highly desirable. Biologically derived odorant receptors have potential as the explosive recognition element in novel biosensors. Caenorhabditis elegans' genome contains over 1,000 uncharacterised candidate chemosensory receptors. It was not known whether any of these respond to volatile chemicals derived from or associated with explosives.

PLOS One, 2011

Background: The SMC5-6 protein complex is involved in the cellular response to DNA damage. It is ... more Background: The SMC5-6 protein complex is involved in the cellular response to DNA damage. It is composed of 6-8 polypeptides, of which Nse1, Nse3 and Nse4 form a tight sub-complex. MAGEG1, the mammalian ortholog of Nse3, is the founding member of the MAGE (melanoma-associated antigen) protein family and Nse4 is related to the EID (E1A-like inhibitor of differentiation) family of transcriptional repressors.

PLoS ONE, 2014

It is widely accepted that vertebrate G-Protein Coupled Receptors (GPCRs) associate with each oth... more It is widely accepted that vertebrate G-Protein Coupled Receptors (GPCRs) associate with each other as homo-or heterodimers or higher-order oligomers. The C. elegans genome encodes hundreds of olfactory GPCRs, which may be expressed in fewer than a dozen chemosensory neurons, suggesting an opportunity for oligomerisation. Here we show, using three independent lines of evidence: co-immunoprecipitation, bioluminescence resonance energy transfer and a yeast two-hybrid assay that nematode olfactory receptors (ORs) oligomerise when heterologously expressed in yeast. Specifically, the nematode receptor ODR-10 is able to homo-oligomerise and can also form heteromers with the related nematode receptor STR-112. ODR-10 also oligomerised with the rat I7 OR but did not oligomerise with the human somatostatin receptor 5, a neuropeptide receptor. In this study, the question of functional relevance was not addressed and remains to be investigated.

Embo Journal - EMBO J, 2004

Hsp90 is a molecular chaperone essential for the activation and assembly of many key eukaryotic s... more Hsp90 is a molecular chaperone essential for the activation and assembly of many key eukaryotic signalling and regulatory proteins. Hsp90 is assisted and regulated by co-chaperones that participate in an ordered series of dynamic multiprotein complexes, linked to Hsp90s conformationally coupled ATPase cycle. The co-chaperones Aha1 and Hch1 bind to Hsp90 and stimulate its ATPase activity. Biochemical analysis shows that this activity is dependent on the N-terminal domain of Aha1, which interacts with the central segment of Hsp90. The structural basis for this interaction is revealed by the crystal structure of the N-terminal domain (1-153) of Aha1 (equivalent to the whole of Hch1) in complex with the middle segment of Hsp90 (273-530). Structural analysis and mutagenesis show that binding of N-Aha1 promotes a conformational switch in the middle-segment catalytic loop (370-390) of Hsp90 that releases the catalytic Arg 380 and enables its interaction with ATP in the N-terminal nucleotide-binding domain of the chaperone.

Reactive and Functional Polymers, 2012

Reactive and Functional Polymers, 2011

Chitosan–polycaprolactone (CH–PCL) copolymers with brush-like chain structures were synthesized. ... more Chitosan–polycaprolactone (CH–PCL) copolymers with brush-like chain structures were synthesized. Some CH–PCLs with a PCL content less than 50wt% were used to build glial cell line-derived neurotrophic factor (GDNF)-loaded microspheres via an emulsification method using genipin as a cross-linker. The resulting microspheres were spherical with a smooth surface and a diameter less than 40μm; however, their loading efficiency could be higher

Reactive and Functional Polymers, 2014

The thermally activated ring-opening polymerization behavior of benzoxazine based on 4,4 0 -diami... more The thermally activated ring-opening polymerization behavior of benzoxazine based on 4,4 0 -diaminodiphenyl ether was investigated by Fourier transform infrared and differential scanning calorimetry, and the thermal properties of the corresponding polybenzoxazine were studied by dynamic mechanical analysis, thermogravimetry-mass spectrometry, and differential thermal analysis. In the ring-opening polymerization reaction, the C-O-C absorption peak of the oxazine ring at 1,054 cm -1 disappeared first, and the C-N-C absorption intensity of the oxazine ring decreased gradually with time rising. The activation energies of the non-isothermal polymerization are 83.4 and 87.4 kJ mol -1 evaluated with Kissinger and Flynn-Wall-Ozawa methods, respectively. Dynamic mechanical analysis shows the glass transition temperature of the resultant polybenzoxazine is 188°C. In the thermal degradation, the 10 % mass loss temperature of the polybenzoxazine is 353°C and the char yield is about 48 % at 800°C in nitrogen, while 415°C and close to 0 % at 650°C in air.

Reactive and Functional Polymers, 2013

ABSTRACT

Polymer Degradation and Stability, 2013

PLoS ONE, 2011

Background: The SMC5-6 protein complex is involved in the cellular response to DNA damage. It is ... more Background: The SMC5-6 protein complex is involved in the cellular response to DNA damage. It is composed of 6-8 polypeptides, of which Nse1, Nse3 and Nse4 form a tight sub-complex. MAGEG1, the mammalian ortholog of Nse3, is the founding member of the MAGE (melanoma-associated antigen) protein family and Nse4 is related to the EID (E1A-like inhibitor of differentiation) family of transcriptional repressors.

Molecular Microbiology, 2005

We demonstrate a role for Qri2 in the essential DNA repair function of the Smc5/6 complex in Sacc... more We demonstrate a role for Qri2 in the essential DNA repair function of the Smc5/6 complex in Saccharomyces cerevisiae. We generated temperature-sensitive (ts) mutants in QRI2 and characterized their properties. The mutants arrest after S phase and prior to mitosis. Furthermore, the arrest is dependant on the Rad24 checkpoint, and is also accompanied by phosphorylation of the Rad53 checkpoint effector kinase. The mutants also display genome instability and are sensitive to agents that damage DNA. Two-hybrid screens reveal a physical interaction between Qri2 and proteins that are non-Smc elements of the Smc5/6 DNA repair complex, which is why we propose the name NSE4 for the open reading frame previously known as QRI2. A key role for Nse4 in Smc5/6 function is likely, as overexpressing known subunits of the Smc5/6 complex suppresses nse4ts cell cycle arrest. The nse4ts growth arrest is non-lethal and unlike the catastrophic nuclear fragmentation phenotype of smc6ts mutants, the nucleus remains intact; replicative intermediates and sheared DNA are not detected. This could imply a role for Nse4 in maintenance of higher order chromosome structure.

Current Microbiology, 2005

Several Cry1Ac binding proteins from midgut of Helicoverpa armigera were purified using toxin-aff... more Several Cry1Ac binding proteins from midgut of Helicoverpa armigera were purified using toxin-affinity chromatography. Enzyme assays showed that the purified proteins had strong aminopeptidase activity. The N-terminal sequences confidently identified a 124-kDa binding protein as an aminopeptidase N (APN), and some similarity suggests that a 162-kDa binding protein may also be an APN. Two minor binding proteins were not characterized.

Journal of Invertebrate Pathology, 2002

The susceptibilities of the major pests of cotton in Australia, Helicoverpa armigera and Helicove... more The susceptibilities of the major pests of cotton in Australia, Helicoverpa armigera and Helicoverpa punctigera, to some insecticidal proteins from Bacillus thuringiensis were tested by bioassay. A commercial formulation, DiPel, and individual purified insecticidal proteins were tested. H. armigera was consistently more tolerant to B. thuringiensis insecticidal proteins than was H. punctigera, although both were susceptible to only a limited range of these proteins. Only Cry1Ab, Cry1Ac, Cry2Aa, Cry2Ab, and Vip3A killed H. armigera at dosages that could be considered acceptable. There was no significant difference in the toxicities of Cry1Fa and Cry1Ac for H. punctigera but Cry1Fa had little toxicity for H. armigera. The five instars of H. armigera did not differ significantly in their susceptibility to DiPel on the basis of LC50. However, there were significant differences in the susceptibility to Cry1Ac and Cry2Aa of three strains of H. armigera. Bioassays conducted with Cry1Ac and Cry2Aa showed that there was a small but significant negative interaction between these δ-endotoxins.

Journal of Invertebrate Pathology, 2002

The susceptibilities of the major pests of cotton in Australia, Helicoverpa armigera and Helicove... more The susceptibilities of the major pests of cotton in Australia, Helicoverpa armigera and Helicoverpa punctigera, to some insecticidal proteins from Bacillus thuringiensis were tested by bioassay. A commercial formulation, DiPel, and individual purified insecticidal proteins were tested. H. armigera was consistently more tolerant to B. thuringiensis insecticidal proteins than was H. punctigera, although both were susceptible to only a limited range of these proteins. Only Cry1Ab, Cry1Ac, Cry2Aa, Cry2Ab, and Vip3A killed H. armigera at dosages that could be considered acceptable. There was no significant difference in the toxicities of Cry1Fa and Cry1Ac for H. punctigera but Cry1Fa had little toxicity for H. armigera. The five instars of H. armigera did not differ significantly in their susceptibility to DiPel on the basis of LC(50). However, there were significant differences in the susceptibility to Cry1Ac and Cry2Aa of three strains of H. armigera. Bioassays conducted with Cry1Ac and Cry2Aa showed that there was a small but significant negative interaction between these delta-endotoxins.

Current Microbiology, 2005

Several Cry1Ac binding proteins from midgut of Helicoverpa armigera were purified using toxin-aff... more Several Cry1Ac binding proteins from midgut of Helicoverpa armigera were purified using toxin-affinity chromatography. Enzyme assays showed that the purified proteins had strong aminopeptidase activity. The N-terminal sequences confidently identified a 124-kDa binding protein as an aminopeptidase N (APN), and some similarity suggests that a 162-kDa binding protein may also be an APN. Two minor binding proteins were not characterized.

Molecular microbiology, 2005

We demonstrate a role for Qri2 in the essential DNA repair function of the Smc5/6 complex in Sacc... more We demonstrate a role for Qri2 in the essential DNA repair function of the Smc5/6 complex in Saccharomyces cerevisiae . We generated temperaturesensitive ( ts ) mutants in QRI2 and characterized their properties. The mutants arrest after S phase and prior to mitosis. Furthermore, the arrest is dependant on the Rad24 checkpoint, and is also accompanied by phosphorylation of the Rad53 checkpoint effector kinase. The mutants also display genome instability and are sensitive to agents that damage DNA. Twohybrid screens reveal a physical interaction between Qri2 and proteins that are non-Smc elements of the Smc5/6 DNA repair complex, which is why we propose the name NSE4 for the open reading frame previously known as QRI2 . A key role for Nse4 in Smc5/ 6 function is likely, as overexpressing known subunits of the Smc5/6 complex suppresses nse4 ts cell cycle arrest. The nse4 ts growth arrest is non-lethal and unlike the catastrophic nuclear fragmentation phenotype of smc6 ts mutants, the nucleus remains intact; replicative intermediates and sheared DNA are not detected. This could imply a role for Nse4 in maintenance of higher order chromosome structure.

PLOS One, 2010

Background: Automated standoff detection and classification of explosives based on their characte... more Background: Automated standoff detection and classification of explosives based on their characteristic vapours would be highly desirable. Biologically derived odorant receptors have potential as the explosive recognition element in novel biosensors. Caenorhabditis elegans' genome contains over 1,000 uncharacterised candidate chemosensory receptors. It was not known whether any of these respond to volatile chemicals derived from or associated with explosives.

PloS one, 2014

Ionizing radiation (IR) is a common therapeutic agent in cancer therapy. It damages normal tissue... more Ionizing radiation (IR) is a common therapeutic agent in cancer therapy. It damages normal tissue and causes side effects including dermatitis and mucositis. Here we use the feather follicle as a model to investigate the mechanism of IR-induced tissue damage, because any perturbation of feather growth will be clearly recorded in its regular yet complex morphology. We find that IR induces defects in feather formation in a dose-dependent manner. No abnormality was observed at 5 Gy. A transient, reversible perturbation of feather growth was induced at 10 Gy, leading to defects in the feather structure. This perturbation became irreversible at 20 Gy. Molecular and cellular analysis revealed P53 activation, DNA damage and repair, cell cycle arrest and apoptosis in the pathobiology. IR also induces patterning defects in feather formation, with disrupted branching morphogenesis. This perturbation is mediated by cytokine production and Stat1 activation, as manipulation of cytokine levels or ectopic Stat1 over-expression also led to irregular feather branching. Furthermore, AG-490, a chemical inhibitor of Stat1 signaling, can partially rescue IR-induced tissue damage. Our results suggest that the feather follicle could serve as a useful model to address the in vivo impact of the many mechanisms of IR-induced tissue damage.

PLoS ONE, 2010

Background: Automated standoff detection and classification of explosives based on their characte... more Background: Automated standoff detection and classification of explosives based on their characteristic vapours would be highly desirable. Biologically derived odorant receptors have potential as the explosive recognition element in novel biosensors. Caenorhabditis elegans' genome contains over 1,000 uncharacterised candidate chemosensory receptors. It was not known whether any of these respond to volatile chemicals derived from or associated with explosives.

PLOS One, 2011

Background: The SMC5-6 protein complex is involved in the cellular response to DNA damage. It is ... more Background: The SMC5-6 protein complex is involved in the cellular response to DNA damage. It is composed of 6-8 polypeptides, of which Nse1, Nse3 and Nse4 form a tight sub-complex. MAGEG1, the mammalian ortholog of Nse3, is the founding member of the MAGE (melanoma-associated antigen) protein family and Nse4 is related to the EID (E1A-like inhibitor of differentiation) family of transcriptional repressors.

PLoS ONE, 2014

It is widely accepted that vertebrate G-Protein Coupled Receptors (GPCRs) associate with each oth... more It is widely accepted that vertebrate G-Protein Coupled Receptors (GPCRs) associate with each other as homo-or heterodimers or higher-order oligomers. The C. elegans genome encodes hundreds of olfactory GPCRs, which may be expressed in fewer than a dozen chemosensory neurons, suggesting an opportunity for oligomerisation. Here we show, using three independent lines of evidence: co-immunoprecipitation, bioluminescence resonance energy transfer and a yeast two-hybrid assay that nematode olfactory receptors (ORs) oligomerise when heterologously expressed in yeast. Specifically, the nematode receptor ODR-10 is able to homo-oligomerise and can also form heteromers with the related nematode receptor STR-112. ODR-10 also oligomerised with the rat I7 OR but did not oligomerise with the human somatostatin receptor 5, a neuropeptide receptor. In this study, the question of functional relevance was not addressed and remains to be investigated.

Embo Journal - EMBO J, 2004

Hsp90 is a molecular chaperone essential for the activation and assembly of many key eukaryotic s... more Hsp90 is a molecular chaperone essential for the activation and assembly of many key eukaryotic signalling and regulatory proteins. Hsp90 is assisted and regulated by co-chaperones that participate in an ordered series of dynamic multiprotein complexes, linked to Hsp90s conformationally coupled ATPase cycle. The co-chaperones Aha1 and Hch1 bind to Hsp90 and stimulate its ATPase activity. Biochemical analysis shows that this activity is dependent on the N-terminal domain of Aha1, which interacts with the central segment of Hsp90. The structural basis for this interaction is revealed by the crystal structure of the N-terminal domain (1-153) of Aha1 (equivalent to the whole of Hch1) in complex with the middle segment of Hsp90 (273-530). Structural analysis and mutagenesis show that binding of N-Aha1 promotes a conformational switch in the middle-segment catalytic loop (370-390) of Hsp90 that releases the catalytic Arg 380 and enables its interaction with ATP in the N-terminal nucleotide-binding domain of the chaperone.

Reactive and Functional Polymers, 2012

Reactive and Functional Polymers, 2011

Chitosan–polycaprolactone (CH–PCL) copolymers with brush-like chain structures were synthesized. ... more Chitosan–polycaprolactone (CH–PCL) copolymers with brush-like chain structures were synthesized. Some CH–PCLs with a PCL content less than 50wt% were used to build glial cell line-derived neurotrophic factor (GDNF)-loaded microspheres via an emulsification method using genipin as a cross-linker. The resulting microspheres were spherical with a smooth surface and a diameter less than 40μm; however, their loading efficiency could be higher

Reactive and Functional Polymers, 2014

The thermally activated ring-opening polymerization behavior of benzoxazine based on 4,4 0 -diami... more The thermally activated ring-opening polymerization behavior of benzoxazine based on 4,4 0 -diaminodiphenyl ether was investigated by Fourier transform infrared and differential scanning calorimetry, and the thermal properties of the corresponding polybenzoxazine were studied by dynamic mechanical analysis, thermogravimetry-mass spectrometry, and differential thermal analysis. In the ring-opening polymerization reaction, the C-O-C absorption peak of the oxazine ring at 1,054 cm -1 disappeared first, and the C-N-C absorption intensity of the oxazine ring decreased gradually with time rising. The activation energies of the non-isothermal polymerization are 83.4 and 87.4 kJ mol -1 evaluated with Kissinger and Flynn-Wall-Ozawa methods, respectively. Dynamic mechanical analysis shows the glass transition temperature of the resultant polybenzoxazine is 188°C. In the thermal degradation, the 10 % mass loss temperature of the polybenzoxazine is 353°C and the char yield is about 48 % at 800°C in nitrogen, while 415°C and close to 0 % at 650°C in air.

Reactive and Functional Polymers, 2013

ABSTRACT

Polymer Degradation and Stability, 2013

PLoS ONE, 2011

Background: The SMC5-6 protein complex is involved in the cellular response to DNA damage. It is ... more Background: The SMC5-6 protein complex is involved in the cellular response to DNA damage. It is composed of 6-8 polypeptides, of which Nse1, Nse3 and Nse4 form a tight sub-complex. MAGEG1, the mammalian ortholog of Nse3, is the founding member of the MAGE (melanoma-associated antigen) protein family and Nse4 is related to the EID (E1A-like inhibitor of differentiation) family of transcriptional repressors.

Molecular Microbiology, 2005

We demonstrate a role for Qri2 in the essential DNA repair function of the Smc5/6 complex in Sacc... more We demonstrate a role for Qri2 in the essential DNA repair function of the Smc5/6 complex in Saccharomyces cerevisiae. We generated temperature-sensitive (ts) mutants in QRI2 and characterized their properties. The mutants arrest after S phase and prior to mitosis. Furthermore, the arrest is dependant on the Rad24 checkpoint, and is also accompanied by phosphorylation of the Rad53 checkpoint effector kinase. The mutants also display genome instability and are sensitive to agents that damage DNA. Two-hybrid screens reveal a physical interaction between Qri2 and proteins that are non-Smc elements of the Smc5/6 DNA repair complex, which is why we propose the name NSE4 for the open reading frame previously known as QRI2. A key role for Nse4 in Smc5/6 function is likely, as overexpressing known subunits of the Smc5/6 complex suppresses nse4ts cell cycle arrest. The nse4ts growth arrest is non-lethal and unlike the catastrophic nuclear fragmentation phenotype of smc6ts mutants, the nucleus remains intact; replicative intermediates and sheared DNA are not detected. This could imply a role for Nse4 in maintenance of higher order chromosome structure.