GTC Biotherapeutics (fka GTCB)

[gym gravity]

Nexia Biotech has goats that produce spider silk in their milk.

http://www.nexiabiotech.com/en/01_tech/01-bst.php
http://www.eurekalert.org/pub_releases/2002-01/nbi-nau011102.php
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&l...
http://en.wikipedia.org/wiki/Biosteel

wikipedia:
"Biosteel is also a high-strength polyamide fiber material made of spider silk-like protein extracted from milk of transgenic goats. It is registered under the brand name BioSteel. While the attempt to put spider genes into goats and extract the protein from the milk succeeded, the project so far failed to spin it into the fiber."

So far they haven't been able to replicate the spinnerettes:

"In 2000, Nexia, a Canadian biotechnology company, was successful in producing spider silk protein in transgenic goats. These goats carried the gene for spider silk protein, and the milk produced by the goats contained significant quantities of the protein. Attempts to spin the protein into a fiber similar to natural spider silk failed, however. The spider's highly sophisticated spinneret is instrumental in organizing the silk proteins into strong domains. Specifically, the spinneret creates a gradient of protein concentration, pH, and pressure, which drive the protein solution through liquid crystalline phase transitions, ultimately generating the required silk structure (which is a mixture of crystalline and amorphous biopolymer regions). Replicating these complex conditions in lab environment has proved difficult. Nexia attempted to press the protein solution through small extrusion holes in order to simulate the behavior of the spinneret, but this was insufficient to properly organize the fibers. Ultimately, Nexia was forced to abandon research on artificial spider silk, despite having successfully created the silk protein in genetically modified organisms."