Generation of BALB/cJ Nfia conditional knockout mice.

The myeloid cell-specific NFI-A knockout mice were generated by breeding the Nfia floxed mice described above with the Lyz2^Cre knock-in mice. Nfia^flox/flox;Lyz2^Cre/+ mice were crossed to Nfia^flox/flox;Lyz2^+/+ mice to generate Nfia^flox/flox mice with and without Cre. Genotypes were verified for all mice by PCR. Western blotting was also used to confirm that the myeloid cells were negative for Nfia expression. The Nfia^flox/flox;Lyz2^Cre/+ mice, where the expression of the Cre recombinase under the control of the Lyz2 gene promoter inactivates the floxed Nfia allele in the myeloid-lineage cells, served as our myeloid cell-specific knockout. The Nfia^flox/flox;Lyz2^+/+ mice, which do not express the Cre recombinase (and thus, the floxed Nfia allele is still expressed in the myeloid-lineage cells), served as controls.

The mice were bred and housed in a pathogen-free facility in the Division of Laboratory Animal Resources of East Tennessee State University. Wild-type male BALB/cJ littermates (8 to 10 weeks old) were purchased from the Jackson Laboratory (Bar Harbor, ME) and were acclimated to the new environment for a week before surgery. All experiments were conducted in accordance with National Institutes of Health guidelines and were approved by the East Tennessee State University Animal Care and Use Committee.