NIGMS (and other NIH) investigators previously have been able to obtain over 2,500 knockout mouse strains at a negotiated cost from Lexicon. These mouse strains are no longer available directly through Lexicon.
You may now request them, along with an additional 1,000 knockout strains, through Taconic. NIH investigators acquiring a Lexicon knockout mouse through Taconic are expected to place the mouse lines in a NIH-supported mouse repository.
The NIH Guide notice updates the policy and provides more details.