To investigate the role of the yeast telomere-, silencing-, and UAS-binding protein RAP1 in telomere position effects, we have characterized two sets of mutant cells: (1) a set of rap1 alleles (termed the rap1 t alleles) that produce truncated RAP1 proteins missing the carboxy-terminal 144-165 amino acids; and (2) null mutants of the RIF1 gene, encoding a protein capable of interaction with the carboxyl terminus of RAP1. The data presented here indicate that loss of the carboxyl terminus of RAP1 abolishes position effects at yeast telomeres and diminishes silencing at the HML locus. Elimination of position effects in these cells is associated with increased accessibility to the Escherichia coli dam methylase in vivo. Thus, the carboxy-terminal domain of RAP1 is required for telomere position effects. In contrast, rifl deletion alleles increase the frequency of repressed cells. Using the rap1 t alleles to generate wild-type cells differing only in telomere tract lengths, we also show that telomere position effects are highly sensitive to changes in the size (or structure) of the telomeric tract. Longer poly(GI_3T) tracts can increase the frequency of transcriptional repression at the telomere, suggesting that telomeric poly(Gl_3 T) tracts play an active role in the formation or stability of subtelomeric transcriptional states.

Recent evidence has accumulated that the dynamic histone methylation mediated by histone methyltransferases and demethylases plays key roles in regulation of chromatin structure and transcription. In the present study, we show that SET and MYND domain-containing protein 3 (SMYD3), a histone methyltransferase implicated in oncogenesis, directly trans-activates the telomerase reverse transcriptase (hTERT) gene that is essential for cellular immortalization and transformation. SMYD3 occupies its binding motifs on the hTERT promoter and is required for maintenance of histone H3-K4 trimethylation, thereby contributing to inducible and constitutive hTERT expression in normal and malignant human cells. Knocking down SMYD3 in tumor cells abolished trimethylation of H3-K4, attenuated the occupancy by the transactivators c-MYC and Sp1, and led to diminished histone H3 acetylation in the hTERT promoter region, which was coupled with down-regulation of hTERT mRNA and telomerase activity. These results suggest that SMYD3-mediated trimethylation of H3-K4 functions as a licensing element for subsequent transcription factor binding to the hTERT promoter. The present findings provide significant insights into regulatory mechanisms of hTERT/telomerase expression; moreover, identification of the hTERT gene as a direct target of SMYD3 contributes to a better understanding of SMYD3-mediated cellular transformation. [Cancer Res 2007;67(6):2626-31]

Aegilops caudata is an important gene source for wheat breeding. Intensive evaluation of its utilization value is an essential first step prior to its application in breeding. In this research, the agronomical and quality traits of Triticum aestivum-Ae. caudata additions B–G (homoeologous groups not identified) were analyzed and evaluated. Disease resistance tests showed that chromosome D of Ae. caudata might possess leaf rust resistance, and chromosome E might carry stem rust and powdery mildew resistance genes. Investigations into agronomical traits suggested that the introduction of the Ae. caudata chromosome in addition line F could reduce plant height. Grain quality tests showed that the introduction of chromosomes E or F into wheat could increase its protein and wet gluten content. Therefore, wheat-Ae. caudata additions D–F are all potentially useful candidates for chromosome engineering activities to create useful wheat-alien chromosome introgressions. A total of 55 EST-based molecular markers were developed and then used to identify the chromosome homoeologous group of each of the Ae. caudata B–G chromosomes. Marker analysis indicated that the Ae. caudata chromosomes in addition lines B to G were structurally altered, therefore, a large population combined with intensive screening pressure should be taken into consideration when inducing and screening for wheat-Ae. caudata compensating translocations. Marker data also indicated that the Ae. caudata chromosomes in addition lines C–F were 5C, 6C, 7C, and 3C, respectively, while the homoeologous group of chromosomes B and G of Ae. caudata are as yet undetermined and need further research.

bHelicobacter heilmannii is a zoonotic bacterium that has been associated with gastric disease in humans. In this study, the mRNA expression of mucins in the stomach of BALB/c mice was analyzed at several time points during a 1-year infection with this bacterium, during which gastric disease progressed in severity. Markers for acid production by parietal cells and mucous metaplasia were also examined. In the first 9 weeks postinfection, the mRNA expression of Muc6 was clearly upregulated in both the antrum and fundus of the stomach of H. heilmannii-infected mice. Interestingly, Muc13 was upregulated already at 1 day postinfection in the fundus of the stomach. Its expression level remained high in the stomach over the course of the infection. This mucin is, however, not expressed in a healthy stomach, and high expression of this mucin has so far only been described in gastric cancer. In the later stages of infection, mRNA expression of H ؉ /K ؉ -ATPase ␣/␤ and KCNQ1 decreased, whereas the expression of Muc4, Tff2, Dmbt1, and polymeric immunoglobulin receptor (pIgR) increased starting at 16 weeks postinfection onwards, suggesting the existence of spasmolytic polypeptide-expressing metaplasia in the fundus of the stomach. Mucous metaplasia present in the mucosa surrounding low-grade mucosa-associated lymphoid tissue (MALT) lymphoma-like lesions was also histologically confirmed. Our findings indicate that H. heilmannii infection causes severe gastric pathologies and alterations in the expression pattern of gastric mucins, such as Muc6 and Muc13, as well as disrupting gastric homeostasis by inducing the loss of parietal cells, resulting in the development of mucous metaplasia.

A new wheat-Thinopyrum substitution line AS1677, developed from a cross between wheat line ML-13 and wheat-Thinopyrum intermedium ssp. trichophorum partial amphiploid TE-3, was characterized by fluorescence in situ hybridization (FISH)

Dasypyrum breviaristatum and nine related species in Triticeae were analyzed using the random amplified polymorphic DNA (RAPD) technique, in order to understand the genetic relationship and to develop species specific markers. The genome relationship dendrogram shows that D. breviaristatum and D. villosum could not be grouped together, indicating that D. breviaristatum was unlikely to be directly derived from D. villosum, while D. breviaristatum was closest to Thinopyrum intermedium, which implied that they might have similar breeding behaviors when introducing their chromatins into wheat. A D. breviaristatum genome specific RAPD product of 1182bp, was cloned and designated as pDb12H. Sequence analysis revealed that pDb12H was strongly homologuos to a long terminal repeat (LTR) Sabrina retrotransposon newly reported in Hordeum. The pDb12H was converted into a PCR based marker, which allows effectively monitoring the D. breviaristatum chromatin introgression into wheat. Fluorescence in situ hybridization (FISH) suggested that pDb12H was specifically hybridized throughout all D. breviaristatum chromosomes arms except for the terminal and centromeric regions, which can be used to characterize wheat -D. breviaristatum chromosome translocation. The genomes repetitive element will also be useful to study gene interactions between the wheat and alien genomes after the polyploidization.

A genome specific DNA sequence that detects Secale africanum chromatin incorporated into wheat was developed in this study. Random amplified polymorphic DNA (RAPD) analysis was used to search for genome specific DNA sequences of S. africanum in lines, R111, ''mianyang11'' (MY11) and wheat-rye 1RS/1BL translocations R25 and R57. A high copy rye-specific DNA segment pSaD15 940 of the S. africanum genome was obtained. The sequence of pSaD15 did not show any significant homology to other reported sequences in databases and it is therefore a new repetitive sequence of Secale. PCR primers were designed for pSaD15 940 , which amplify a clear 887 bp fragment in S. africanum but not in any wheat. The primers also amplified an 887 bp fragment in other accessions of rye, Chinese Spring-Imperial rye chromosome additions and a diverse range of material carrying different rye chromosomes or chromosomal segments. In situ hybridization showed that probe pSaD15 940 was specifically hybridized throughout all rye chromosomes arms except for the terminal regions. The advantage of the rye-specific probe developed herein compared to those of previous reports is that it has been shown to be widely applicable to other Secale species. The probe will be useful as a molecular marker for the introgression of S. africanum and other rye chromosome segments into the wheat genome.

Natural botanical drugs have attracted attention due to their cancer chemopreventive and chemotherapeutic properties in cancer. Punicalagin (PUN) is the major bioactive component of pomegranate peel, and has been shown to have antioxidant, anti-inflammatory, antiviral, antiproliferation and anticancer properties. PUN has been shown to induce apoptosis in several cancer cell lines. The aim of the present study was to investigate the effect of PUN on HeLa human cervical cancer cells in vitro. The viability of the HeLa cells was assessed following treatment with PUN (0, 12.5, 25, 50, 100 and 200 µM) for 24, 36 and 48 h using a Cell Counting Kit‑8 assay. In addition, the cell cycle distribution, protein expression levels of B‑cell lymphoma 2 (Bcl‑2)‑associated X protein (Bax), Bcl‑2, tissue inhibitor of metalloproteinase (TIMP)-2, TIMP‑3 and the β‑catenin pathway, and the activities of matrix metalloproteinase (MMP)‑2 and MMP‑9 were analyzed following treatment with PUN (0, 25, 50 and 100 µM) for 36 h using cell cycle analysis, western blot analysis and gelatin zymography, respectively. In addition, a wound‑healing assay was used to detect cell migration. PUN led to a number of effects on the HeLa cells, including the inhibition of cell proliferation and cell migration, downregulation of MMP‑2 and MMP‑9, upregulation of TIMP‑2 and TIMP‑3, cell‑cycle arrest in the G1 phase, induction of apoptosis via alterations of Bcl‑2 and Bax, and downregulation of β‑catenin and its downstream proteins, cyclin D1 and c-myc. These results suggested that PUN may have chemopreventive and chemotherapeutic effects against cervical cancer in humans through inhibition of the β-catenin signaling pathway.