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Dan Piestun

Publications and source records attributed to Dan Piestun.

2 recordsLinked to original sources

Nanog transforms NIH3T3 cells and targets cell-type restricted genes.

The transcription factor Nanog is uniquely expressed in embryonic stem (ES) cells and in germ cell tumors and is important for self-renewal. To understand the relation between this and cell transformation, we expressed Nanog in NIH3T3 cells, and these cells showed an increased growth rate and a transformed phenotype as demonstrated by foci formation and colony growth in soft agar. This suggests that Nanog possesses an oncogenic potential that may be related to the role it plays in germ cell tumors and to its function in self renewal of ES cells. We studied the transcription targets of Nanog using microarrays to identify Nanog regulated genes. The list of genes regulated by Nanog was unique for each cell type and more than 10% of the Nanog regulated genes, including transcription factors, are primary Nanog targets since their promoters bind Nanog in ES cells. Some of these target genes can explain the transformation of NIH3T3.

Animals↗

Rose scent: genomics approach to discovering novel floral fragrance-related genes.

For centuries, rose has been the most important crop in the floriculture industry; its economic importance also lies in the use of its petals as a source of natural fragrances. Here, we used genomics approaches to identify novel scent-related genes, using rose flowers from tetraploid scented and nonscented cultivars. An annotated petal EST database of approximately 2100 unique genes from both cultivars was created, and DNA chips were prepared and used for expression analyses of selected clones. Detailed chemical analysis of volatile composition in the two cultivars, together with the identification of secondary metabolism-related genes whose expression coincides with scent production, led to the discovery of several novel flower scent-related candidate genes. The function of some of these genes, including a germacrene D synthase, was biochemically determined using an Escherichia coli expression system. This work demonstrates the advantages of using the high-throughput approaches of genomics to detail traits of interest expressed in a cultivar-specific manner in nonmodel plants. EST sequences were submitted to the GenBank database (accession numbers BQ 103855 to BQ 106728).

Alkyl and Aryl Transferases↗