Subject: Scientists Find `Switch' to Halt Bacteria Growth 
Date: Published: 10/19/90 (82 lines)
Source: Wall Street Journal. Copyright Dow Jones & Co. Inc.

    Technology:
    Scientists Find
    `Switch' to Halt
    Bacteria Growth
    ----
    By Marilyn Chase
    Staff Reporter of The Wall Street Journal

    STANFORD, Calif.  -- A team of Stanford University
 scientists has solved one of biology's most basic puzzles,
 identifying the "off switch" that stops bacteria from
 replicating.
    The discovery sheds light on the basic processes of
 growth.  Experts said yesterday it could illuminate new paths
 in cancer and AIDS research, as well as in the manufacture of
 biotechnology products.
    Working with E. coli, a common bacterium, the team
 discovered a protein that halts replication of the bacterial
 DNA, the organism's genetic code, and in turn stops cells
 from dividing.  This off switch, called the 33kdA protein,
 performs a crucial step without which cells grow wildly and
 out of control, as they do in cancer.
    The finding comes from the laboratory of Arthur Kornberg,
 a Stanford biochemistry professor and a past Nobel prize
 winner for his earlier studies on the replication of DNA. The
 lead author of the report is Deog Su Hwang, a postdoctoral
 fellow in the Kornberg lab.  Their report is published in the
 October issue of the journal Cell.
    "Clearly, this is a major new finding about the
 biochemistry of DNA replication by Dr. Kornberg, the founding
 father of the whole field," said John Minna, a researcher at
 the National Cancer Institute.  There are many diseases in
 which a cell's ability to control DNA replication is
 impaired, he said, and thus the discovery of such a regulator
 switch is "very exciting."
    "It could have profound implications for cancer and AIDS,"
 Mr. Minna said.
    Dr. Kornberg, who worked on the project for nine years,
 emphasized that the discovery remains a basic research tool
 for now -- but one which opens a window on a much larger
 picture.
    "If you know the anatomy of the switch," Dr. Kornberg
 said, "if you have the hood off and can see how the motor
 works, you can then determine what factors provoke it to get
 started replicating or keep it in check."
    "One obvious question," said NCI's Mr. Minna, "is whether
 there exists a similar protein in human cells.  If so, does it
 act as a tumor-suppressor gene, to hold DNA replication in
 check?  "
    Future experiments in larger animals and in humans must
 answer that question.  Dr. Kornberg, who was out of the
 country and unavailable for comment, asserted in a prepared
 statement that it is "almost inevitable" that the new finding
 will guide research on human growth.
    Elliott Crooke, a fellow in the Kornberg laboratory,
 explained in an interview yesterday that so many bacterial
 proteins have human counterparts that "we feel confident {it}
 could very well carry through to these higher organisms."
    He predicted that scientists will be able to "exploit the
 negative effect" of the protein in antibiotic development, as
 well as in cancer treatment, where doctors strive to arrest
 runaway growth.
    On the other hand, neutralizing the off switch may become
 a goal for biotech firms, which harness these common bacteria
 as tiny factories for churning out biotechnology products.
 Inactivating that switch, he speculated, could potentially
 boost the production of gene-spliced proteins.  These include
 such products as human growth hormone or the heart attack
 drug TPA. 
    "We can hypothesize about how it will carry through, but
 we set out to find a basic tool, and Deog Su Hwang found it,"
 said Mr. Crooke.  "Every time we find one of these factors,
 it's another piece of the jigsaw puzzle."

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