Centromeres are the chromosomal regions promoting kinetochore assembly for chromosome segregation... more Centromeres are the chromosomal regions promoting kinetochore assembly for chromosome segregation. In many eukaryotes, the centromere consists of up to mega base pairs of DNA. On such "regional centromeres," kinetochore assembly is mainly defined by epigenetic regulation [1]. By contrast, a clade of budding yeasts (Saccharomycetaceae) has a "point centromere" of 120-200 base pairs of DNA, on which kinetochore assembly is defined by the consensus DNA sequence [2, 3]. During evolution, budding yeasts acquired point centromeres, which replaced ancestral, regional centromeres [4]. All known point centromeres among different yeast species share common consensus DNA elements (CDEs) [5, 6], implying that they evolved only once and stayed essentially unchanged throughout evolution. Here, we identify a yeast centromere that challenges this view: that of the budding yeast Naumovozyma castellii is the first unconventional point centromere with unique CDEs. The N. castellii ...
We investigated intracellular signalling pathways for apoptosis induced by epigallocatechin-3-gal... more We investigated intracellular signalling pathways for apoptosis induced by epigallocatechin-3-gallate (EGCG) as compared with those induced by a toxic chemical substance (etoposide, VP16) or the death receptor ligand [tumour necrosis factor (TNF)]. EGCG as well as VP16 and TNF induced activation of two apoptosis-regulating mitogen-activated protein (MAP) kinases, namely c-Jun N-terminal kinase (JNK) and p38 MAP kinase, in both human leukaemic U937 and OCI-AML1a cells. In U937 cells, the apoptosis and activation of caspases-3 and −9 induced by EGCG but not VP16 and TNF were inhibited with SB203580, a specific inhibitor of p38, while those induced by EGCG and VP16 but not TNF were inhibited with SB202190, a rather broad inhibitor of JNK and p38. In contrast, the EGCG-induced apoptosis in OCI-AML1a cells was resistant to SB203580 but not to SB202190. Unlike TNF, EGCG did not induce the activation of nuclear factor-κB but rather induced the primary activation of caspase-9. N-Acetyl-l-cy...
c‐Ski, originally identified as an oncogene product, induces myogenic differentiation in nonmyoge... more c‐Ski, originally identified as an oncogene product, induces myogenic differentiation in nonmyogenic fibroblasts through transcriptional activation of muscle regulatory factors. Although c‐Ski does not bind to DNA directly, it binds to DNA through interaction with Smad proteins and regulates signaling activities of transforming growth factor‐β (TGF‐β). In the present study, we show that c‐Ski activates the myogenin promoter independently of regulation of endogenous TGF‐β signaling. Expression of myogenin is regulated by a transcription factor complex containing proteins of the MyoD family and the myocyte enhancer factor 2 (MEF2) family. c‐Ski acts on the MyoD–MEF2 complex and modulates the activity of MyoD in myogenin promoter regulation. Interestingly, histone deacetylase (HDAC) inhibitors up‐regulated basal activity of transcription from a MyoD‐responsive reporter, although c‐Ski failed to further augment this transcription in the presence of HDAC inhibitors. c‐Ski is observed bot...
Centromeres are the chromosomal regions promoting kinetochore assembly for chromosome segregation... more Centromeres are the chromosomal regions promoting kinetochore assembly for chromosome segregation. In many eukaryotes, the centromere consists of up to mega base pairs of DNA. On such "regional centromeres," kinetochore assembly is mainly defined by epigenetic regulation [1]. By contrast, a clade of budding yeasts (Saccharomycetaceae) has a "point centromere" of 120-200 base pairs of DNA, on which kinetochore assembly is defined by the consensus DNA sequence [2, 3]. During evolution, budding yeasts acquired point centromeres, which replaced ancestral, regional centromeres [4]. All known point centromeres among different yeast species share common consensus DNA elements (CDEs) [5, 6], implying that they evolved only once and stayed essentially unchanged throughout evolution. Here, we identify a yeast centromere that challenges this view: that of the budding yeast Naumovozyma castellii is the first unconventional point centromere with unique CDEs. The N. castellii ...
We investigated intracellular signalling pathways for apoptosis induced by epigallocatechin-3-gal... more We investigated intracellular signalling pathways for apoptosis induced by epigallocatechin-3-gallate (EGCG) as compared with those induced by a toxic chemical substance (etoposide, VP16) or the death receptor ligand [tumour necrosis factor (TNF)]. EGCG as well as VP16 and TNF induced activation of two apoptosis-regulating mitogen-activated protein (MAP) kinases, namely c-Jun N-terminal kinase (JNK) and p38 MAP kinase, in both human leukaemic U937 and OCI-AML1a cells. In U937 cells, the apoptosis and activation of caspases-3 and −9 induced by EGCG but not VP16 and TNF were inhibited with SB203580, a specific inhibitor of p38, while those induced by EGCG and VP16 but not TNF were inhibited with SB202190, a rather broad inhibitor of JNK and p38. In contrast, the EGCG-induced apoptosis in OCI-AML1a cells was resistant to SB203580 but not to SB202190. Unlike TNF, EGCG did not induce the activation of nuclear factor-κB but rather induced the primary activation of caspase-9. N-Acetyl-l-cy...
c‐Ski, originally identified as an oncogene product, induces myogenic differentiation in nonmyoge... more c‐Ski, originally identified as an oncogene product, induces myogenic differentiation in nonmyogenic fibroblasts through transcriptional activation of muscle regulatory factors. Although c‐Ski does not bind to DNA directly, it binds to DNA through interaction with Smad proteins and regulates signaling activities of transforming growth factor‐β (TGF‐β). In the present study, we show that c‐Ski activates the myogenin promoter independently of regulation of endogenous TGF‐β signaling. Expression of myogenin is regulated by a transcription factor complex containing proteins of the MyoD family and the myocyte enhancer factor 2 (MEF2) family. c‐Ski acts on the MyoD–MEF2 complex and modulates the activity of MyoD in myogenin promoter regulation. Interestingly, histone deacetylase (HDAC) inhibitors up‐regulated basal activity of transcription from a MyoD‐responsive reporter, although c‐Ski failed to further augment this transcription in the presence of HDAC inhibitors. c‐Ski is observed bot...
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