|
BACKGROUND: There is currently no means to specifically
control the expression of genes introduced into diatoms. Diatoms are characterized
by their silicified cell walls, which can be found in an endless variety of
intricate and ornate shapes. There is much interest in developing techniques
of nanofabrication using silica-based materials, and the diatom is the organism
of choice in understanding how biological systems carry out silica nanofabrication.
By placing genes involved in the formation of silica cell wall structures under
the control of the nitrate transporter control regions, we can modify their
expression. One goal is to modify the silicified structures that are normally
found in a given diatom species and be able to "tailor-make" structures
in a specific manner for applications in nanofabrication.
DESCRIPTION: The applications for this invention are in the
controlled expression of genes introduced into diatoms, to study and modify
diatom metabolism, and make useful products. The control regions for diatom
nitrate transporter genes, which when fused to a target gene, will control the
expression of that gene depending on the nitrogen source in diatom growth medium.
These nitrate transporter gene promoters from the diatom Cylindrotheca fusiformis
have been isolated. Expression of the nitrate transporter genes is controlled
by the nitrogen source in the medium. The genes are expressed under nitrogen
starvation and in the presence of nitrate and nitrite. Adding ammonium to cells
grown in nitrate turns off nitrate transporter gen expression completely within
minutes. Placing cells grown in ammonium into nitrate medium turns on the genes
completely within minutes. Thus, simply by changing the nitrogen source in the
growth medium we can rapidly and completely turn on or off genes placed under
these control regions. Promoter genes can then be controlled by altering the
nitrogen source in the growth medium, turning them on or off at will.
ADVANTAGES: There are currently no techniques available for
the specific control of gene expression in diatoms, so the invention is completely
novel.
CASE NUMBER: SD98-084
INQUIRIES TO: invent@ucsd.edu
|
