Gene Literature Dashboard

T-cell derived suppressor factors (TsF) specific for the random copolymers L-glutamic acid60-L-alanine30-Ltyrosine10 and L-glutamic acid60-L-alanine40, referred to as GAT and GA, respectively, were prepared and partially purified on the approprate antigen immunoadsorbents. GAT-TsF obtained from nonresponder DBA/1 (H-2q) and SJL (H-2s) mice were passed over immunoadsorbents prepared from normal guinea pig serum (NGPS) or guinea pig anti-idiotype antiserum (anti-CGAT) specific for a common cross-reactive idiotype found on most anti-GAT antibodies in all mouse strains tested. Both the directly suppressive activity of the GAT-TsF and the ability of GAT-TsF to induce new suppressor T cells (Ts2) in vitro were adsorbed to and fully recoverable from the guinea pig anti-CGAT-Sepharose immunoadsorbent, while the TsF passed through the control NGPS-Sepharose without appreciable binding. The SJL GAT-TsF specifically eluted from anti-CGAT-immunoadsrobents was shown to still posses I-J determinants. These data provide evidence suggesting a sharing of V region structures between B-cell antibody and T-cell suppressor factor specific for an antigen (GAT) under Ir gene control, in agreement with earlier studies on T and B-cell alloreceptors, T-cell helper factors, and T and B-cell receptors for conventional antigens.

Studies were made of the synthesis of the coupling factor complex (F1--F0) of oxidative phosphorylation after prophage induction of a set of Escherichia coli strains lysogenic for defective transducing phage lambda asn, lambda uncA, or lambda bglC. The transducing phages had been isolated from a strain of E. coli carrying prophage lambda cI857 S7 within the bglB gene located near the unc gene cluster [Miki, T., Hiraga, S., Nagata, T. & Yura, T. (1978) Proc. Natl. Acad. Sci. USA 75, 5099--5103]. When lysogenic cells carrying lambda asn and lambda cI857 S7 were induced at high temperature, synthesis of the F1-ATPase portion of the complex increased to severalfold that of the noninduced cells. In contrast, no increase was observed upon thermoinduction of cells carrying lambda uncA or lambda bglC. The number of membrane sites that could bind purified F1-ATPase also increased significantly upon induction by lambda asn but not by lambda uncA or lambda bglC. In addition, F1-depleted membranes prepared from lambda asn-induced bacteria required more dicyclohexylcarbodiimide to seal the proton pathway than did those from noninduced bacteria. These results strongly suggest that lambda asn carries a set of bacterial genes coding for all the F1 polypeptides (the alpha, beta, gamma, delta, and probably the epsilon subunits) and at least some of the genes involved in formation of F0 polypeptides. Although lambda uncA carries the structural gene (uncA) for the alpha subunit of F1-ATPase, it apparently does not carry the whole set of F1--F0 genes.

The following properties of the cytoplasmic progestin receptor were studied in the hypothalamus, cortex, pituitary and uterus of the estrogen-primed castrated adult female rat using the highly potent progestin R 5020 (promegestone). (a) Sedimentation pattern. In sucrose density gradients, the R 5020-progestin receptor complex sedimented with a coefficient of about 6 to 7S. (b) Binding parameters. R 5020 bound to the progestin receptor with an intrinsic dissociation constant of about 10(-9) M as measured by a Dextran-coated charcoal (DCC) technique. The number of binding sites, however, differed widely. (c) Specificity. Only progestins competed for [3H]R 5020 binding. (d) Estrogen-dependency. In both immature and castrated adult rats, estrogen administration increased the number of R 5020-specific binding sites, assayed in vitro by a DCC technique, in the uterus, pituitary and hypothalamus, but not in the amygdala, hippocampus nor in the cortex. The increase was maximum between 40 and 48 h after priming with the potent estrogen, moxestrol, and could not be induced by androgens nor by progestins.