Acute-phase responses in transgenic mice with CNS overexpression of IL-1 receptor antagonist

The interleukin-1 (IL-1) receptor antagonist (IL-1ra) is an endogenous antagonist that blocks the effects of the proinflammatory cytokines IL-1α and IL-1β by occupying the type I IL-1 receptor. Here we describe transgenic mice with astrocyte-directed overexpression of the human secreted IL-1ra (hsIL-1ra) under the control of the murine glial fibrillary acidic protein (GFAP) promoter. Two GFAP-hsIL-1ra strains have been generated and characterized further: GILRA2 and GILRA4. These strains show a brain-specific expression of the hsIL-1ra at the mRNA and protein levels. The hsIL-1ra protein was approximated to ∼50 ng/brain in cytosolic fractions of whole brain homogenates, with no differences between male and female mice or between the two strains. Furthermore, the protein is secreted, inasmuch as the concentration of hsIL-1ra in the cerebrospinal fluid was 13 (GILRA2) to 28 (GILRA4) times higher in the transgenic mice than in the control animals. To characterize the transgenic phenotype, GILRA mice and nontransgenic controls were injected with recombinant human IL-1β (central injection) or lipopolysaccharide (LPS, peripheral injection). The febrile response elicited by IL-1β (50 ng/mouse icv) was abolished in hsIL-1ra-overexpressing animals, suggesting that the central IL-1 receptors were occupied by antagonist. The peripheral LPS injection (25 μg/kg ip) triggered a fever in overexpressing and control animals. Moreover, no differences were found in LPS-induced (100 and 1,000 μg/kg ip; 1 and 6 h after injection) IL-1β and IL-6 serum levels between GILRA and wild-type mice. On the basis of these results, we suggest that binding of central IL-1 to central IL-1 receptors is not important in LPS-induced fever or LPS-induced IL-1β and IL-6 plasma levels.

Expression of the RolC Gene in Transgenic Plants of Salpiglossis sinuata L.

The phenotypic expression and inheritance of the rolC gene in the transgenic plants of Salpiglossis sinuata L. were investigated. The chasmogamous salpiglossis plants with solid yellow flower color (ccrrDD) were transformed with Agrobacterium tumefaciens strains LBA4404 and EHA101 carrying rolC, GUS, and NPTII genes via a leaf disc co-cultivation system. The transgenic plants were shorter in plant height, produced more branches with a compact growth habit, and developed smaller flowers and narrower leaves as compared to the control plant. While the transgenic plants showed the same corolla color and color shades as the parental line, they became male sterile. A backcross between a male-sterile transgenic plant (ccrrDD plus rolC) and a nontransformed red-flowering line (ccRRDD) produced a progeny with red flower color and the same altered growth habit as the transgenic female parent. Only 4 out of 32 plants in this progeny population showed the negative GUS staining as well as the non transgenic phenotype. These results suggest that at least two copies of the rolC gene were integrated into one homologous chromosome pair during transformation and that a cross-over event may have occurred during meiosis.