Sigma-Aldrich and Sangamo BioSciences Announce the Achievement of Key Throughput...

Sigma-Aldrich and Sangamo BioSciences Announce the Achievement of Key
Throughput Milestone in Research Reagents Agreement

Milestone Achieved A Year Ahead of Schedule

ST. LOUIS and RICHMOND, Calif., Jan. 12 /PRNewswire-FirstCall/ -- Sangamo
BioSciences, Inc. (Nasdaq: SGMO) today announced it has reached a major
production capacity milestone as part of its agreement with Sigma-Aldrich
Corporation (Nasdaq: SIAL) to commercialize zinc finger nuclease reagents
(ZFNs) for research applications. The milestone triggers a payment of $1.0
million to Sangamo.

"Reaching this production milestone more than one year ahead of schedule
represents an important step in our plans to develop high value ZFN research
reagents for our customers," said Dr. David Smoller, President of
Sigma-Aldrich's Research Biotech Business Unit. "Our CompoZr(TM) ZFN platform
of reagents has captured the interest of the biotechnology research community.
CompoZr reagents provide researchers with the ability to target and precisely
manipulate the genome of living cells, resulting in cell lines or whole
organisms with defined gene deletions, insertions, or corrections. ZFNs can be
designed to target any gene in any organism and used to rapidly make precise
changes to a cell's characteristics. Our aim is to provide CompoZr reagents
to any investigator's 'favorite gene'. As the exclusive licensee and
distributor of ZFN-based reagents for research purposes, we are pleased with
Sangamo's robust and scalable approach that is helping us meet the high demand
for ZFN reagents."

The ability to selectively modify or control specific genes is emerging as a
critical tool in modern biotechnology. Zinc finger DNA-binding proteins (ZFPs)
are the dominant class of naturally-occurring transcription factors in
organisms from yeast to humans. Transcription factors, which are found in the
nucleus of every cell, bind to DNA to regulate gene expression. Though there
are many kinds of transcription factors, only ZFPs are amenable to engineering
and precise targeting to a particular gene, or genes, of interest. By
engineering ZFPs that recognize a specific DNA sequence, Sangamo scientists
have enabled researchers to precisely modify targeted genes and control gene
expression. This technology has the potential to play a major role in bringing
new discoveries in genomics to the marketplace.

"Our ZFN technology is the gold standard for genome editing in cells and whole
organisms," said Edward Lanphier, Sangamo's President and CEO. "There is a
growing appreciation of the numerous applications of ZFP-based reagents in
functional genomics, target validation, drug discovery, process improvement in
biopharmaceutical manufacturing and the generation of transgenic animals. We
are delighted with the progress that has been made in our collaboration with
Sigma-Aldrich. Familiarity and success with our technology at the research
level should lead to commercial success in this field as well as an
appreciation of the broad therapeutic uses of our technology platform."

Sigma-Aldrich's agreement with Sangamo Biosciences, initiated in July 2007,
provides Sigma-Aldrich with the exclusive right to utilize Sangamo's ZFP
technology to develop and commercialize products for use as research reagents
and to offer services in the research field. Sigma-Aldrich's CompoZr
gene-editing technology was recently recognized as one of the Top 10
Innovations of 2008 by The Scientist and was included in the magazine's
inaugural list of the most outstanding products to enter the life sciences
market. For more information on Sigma-Aldrich's CompoZr ZFN technology
platform, visit http://www.compozrzfn.com or contact a sales representative at
zfn@sial.com.

About Sigma-Aldrich

Sigma-Aldrich is a leading Life Science and High Technology company. Its
biochemical and organic chemical products and kits are used in scientific and
genomic research, biotechnology, pharmaceutical development, the diagnosis of
disease and as key components in pharmaceutical and other high technology
manufacturing. The Company has customers in life science companies, university
and government institutions, hospitals, and in industry. Over one million
scientists and technologists use its products. Sigma-Aldrich operates in 36
countries and has 8,000 employees providing excellent service worldwide.
Sigma-Aldrich is committed to Accelerating Customer Success through Innovation
and Leadership in Life Science, High Technology and Service. For more
information about Sigma-Aldrich, please visit its award-winning Web site at
http://www.sigma-aldrich.com.

About Sangamo

Sangamo BioSciences, Inc. is focused on the research and development of novel
DNA-binding proteins for therapeutic gene regulation and modification. The
most advanced ZFP Therapeutic(TM) development program is currently in Phase 2
clinical trials for evaluation of safety and clinical effect in patients with
diabetic neuropathy and ALS. Other therapeutic development programs are
focused on stem cell mobilization, HIV/AIDS, cancer, neuropathic pain,
Parkinson's disease and monogenic diseases. Sangamo's core competencies
enable the engineering of a class of DNA-binding proteins known as zinc finger
DNA-binding proteins (ZFPs). By engineering ZFPs that recognize a specific
DNA sequence Sangamo has created ZFP transcription factors (ZFP TF(TM)) that
can control gene expression and, consequently, cell function. Sangamo is also
developing sequence-specific ZFP Nucleases (ZFN(TM)) for gene modification.
Sangamo has established strategic partnerships with companies outside the
human therapeutic area including Dow AgroSciences, Sigma-Aldrich Corporation
and several companies applying its ZFP Technology to enhance the production of
protein pharmaceuticals. For more information about Sangamo, visit the
company's web site at www.sangamo.com.

This press release may contain forward-looking statements based on
Sigma-Aldrich's and Sangamo's current expectations. These forward-looking
statements include, without limitation, references to the research and
development of novel ZFNs, potential therapeutic, medical research and
pharmaceutical applications of the ZFN technology and the timing of initiation
of clinical trials by Sangamo. Actual results may differ materially from these
forward-looking statements due to a number of factors, including technological
challenges, the ability of Sangamo and Sigma-Aldrich to develop commercially
viable products and technological developments by our competitors. See the SEC
filings, and in particular, the risk factors described in the Annual Report on
Form 10-K and most recent Quarterly Report on Form 10-Q of each of Sangamo and
Sigma-Aldrich. Neither Sigma-Aldrich nor Sangamo assumes any obligation to
update the forward-looking information contained in this press release.

SOURCE Sangamo BioSciences, Inc.

Elizabeth Wolffe, Ph.D. of Sangamo BioSciences, Inc., +1-510-970-6000, x271,
ewolffe@sangamo.com; or Sean Battles of Sigma-Aldrich, +1-314-286-7616 ,
sean.battles@sial.com