January 21, 1999
Vol. 18 No. 8

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    Preuss wins Junior Award for her contributions to cell biology field

    By Sharon Parmet
    Medical Center Public Affairs

    The American Society of Cell Biology granted Daphne Preuss, Assistant Professor in Molecular Genetics & Cell Biology, the 1998 Junior Women in Cell Biology Award.

    The Junior Award recognizes outstanding achievement in cell biology and is given to a woman in an early stage of her career who has made exceptional scientific contributions to cell biology.

    The award also honors those who exhibit potential for continuing a high level of scientific endeavors while fostering career development of young scientists.

    Preuss’s research focuses specifically on plant pollination and the interaction of pollen and egg cells.

    She uses genetic and biochemical approaches to identify the mechanisms that these cells use to recognize one another.

    When a pollen grain lands on the female parts of a flower, a pollen tube forms near the ovary to deliver sperm to the eggs.

    These tubes need to recognize and avoid eggs that have already been fertilized and grow toward eggs that have not yet been fertilized. Preuss has cloned a gene responsible for guiding the pollen tube and has placed mutants where the pollen tube grows randomly.

    Preuss also is exploring a part of plant chromosomes called the centromere, which is crucial for successful cell division. After a cell’s genetic information duplicates but before the cell divides, two sets of tiny fibers form and attach to the chromosomes at the centromere––a middle region of the chromosome. As the fibers shorten, the two sets of chromosomes are pulled to opposite ends of the cell so that when it divides, each new daughter cell has a full complement of chromosomes.

    If researchers could create artificial chromosomes with functional centromeres, then therapeutic genes could be introduced to cells. Current gene therapy does not ensure that inserted genes will be passed on to daughter cells.

    If an implanted gene integrates into a cell’s DNA, it may not be expressed properly. Moreover, by landing in a natural chromosome, it may jump into and inactivate important genes. The ability to construct artificial chromosomes would resolve these problems. By engineering the DNA sequences on the entire artificial chromosome, gene expression could be easily controlled without altering the function of normal genes.