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排序方式: 共有265条查询结果,搜索用时 46 毫秒
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Lovastatin selectively inhibits ras activation of the 12-O-tetradecanoylphorbol-13-acetate response element in mammalian cells. 总被引:1,自引:0,他引:1 下载免费PDF全文
D Defeo-Jones E M McAvoy R E Jones G A Vuocolo K M Haskell R J Wegrzyn A Oliff 《Molecular and cellular biology》1991,11(4):2307-2310
To evaluate ras-mediated signal transduction, an alkaline phosphatase gene (SEAP) was placed under the control of the ras-inducible phorbol ester response element (TRE) in murine fibroblasts (TRE-SEAP cells). The Kirsten ras gene was placed under the control of the glucocorticoid-inducible mouse mammary tumor virus promoter and introduced into the TRE-SEAP cells. Dexamethasone increased ras expression in the TRE-SEAP cells carrying the Kirsten ras gene and stimulated SEAP activity 25-fold. Lavostatin blocked dexamethasone induction of SEAP activity (50% inhibitory concentration, 0.5 microM) but did not affect phorbol ester-induced SEAP activity in the same cells. Lovastatin also did not block forskolin induction of SEAP activity in cells expressing SEAP under the control of the cyclic AMP response element. 相似文献
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Litman GW; Rast JP; Shamblott MJ; Haire RN; Hulst M; Roess W; Litman RT; Hinds- Frey KR; Zilch A; Amemiya CT 《Molecular biology and evolution》1993,10(1):60-72
Immunoglobulins are encoded by a large multigene system that undergoes
somatic rearrangement and additional genetic change during the development
of immunoglobulin-producing cells. Inducible antibody and antibody-like
responses are found in all vertebrates. However, immunoglobulin possessing
disulfide-bonded heavy and light chains and domain-type organization has
been described only in representatives of the jawed vertebrates. High
degrees of nucleotide and predicted amino acid sequence identity are
evident when the segmental elements that constitute the immunoglobulin gene
loci in phylogenetically divergent vertebrates are compared. However, the
organization of gene loci and the manner in which the independent elements
recombine (and diversify) vary markedly among different taxa. One striking
pattern of gene organization is the "cluster type" that appears to be
restricted to the chondrichthyes (cartilaginous fishes) and limits
segmental rearrangement to closely linked elements. This type of gene
organization is associated with both heavy- and light-chain gene loci. In
some cases, the clusters are "joined" or "partially joined" in the germ
line, in effect predetermining or partially predetermining, respectively,
the encoded specificities (the assumption being that these are expressed)
of the individual loci. By relating the sequences of transcribed gene
products to their respective germ-line genes, it is evident that, in some
cases, joined-type genes are expressed. This raises a question about the
existence and/or nature of allelic exclusion in these species. The
extensive variation in gene organization found throughout the vertebrate
species may relate directly to the role of intersegmental
(V<==>D<==>J) distances in the commitment of the individual
antibody-producing cell to a particular genetic specificity. Thus, the
evolution of this locus, perhaps more so than that of others, may reflect
the interrelationships between genetic organization and function.
相似文献
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Haskell Andrew; Nadel Ethan R.; Stachenfeld Nina S.; Nagashima Kei; Mack Gary W. 《Journal of applied physiology》1997,83(2):407-413
Haskell, Andrew, Ethan R. Nadel, Nina S. Stachenfeld, KeiNagashima, and Gary W. Mack. Transcapillary escape rate of albuminin humans during exercise-induced hypervolemia. J. Appl. Physiol. 83(2): 407-413, 1997.To test thehypotheses that plasma volume (PV) expansion 24 h after intenseexercise is associated with reduced transcapillary escape rate ofalbumin (TERalb) and that localchanges in transcapillary forces in the previously active tissues favorretention of protein in the vascular space, we measured PV,TERalb, plasma colloid osmoticpressure (COPp), interstitialfluid hydrostatic pressure (Pi), and colloid osmotic pressure in legmuscle and skin and capillary filtration coefficient (CFC) in the armand leg in seven men and women before and 24 h after intense uprightcycle ergometer exercise. Exercise expanded PV by 6.4% at 24 h (43.9 ± 0.8 to 46.8 ± 1.2 ml/kg, P < 0.05) and decreased total protein concentration (6.5 ± 0.1 to6.3 ± 0.1 g/dl, P < 0.05) andCOPp (26.1 ± 0.8 to 24.3 ± 0.9 mmHg, P < 0.05), although plasmaalbumin concentration was unchanged. TERalb tended to decline (8.4 ± 0.5 to 6.5 ± 0.7%/h, P = 0.11) and was correlated with the increase in PV(r = 0.69,P < 0.05). CFC increased in the leg(3.2 ± 0.2 to 4.3 ± 0.5 µl · 100 g1 · min1 · mmHg1,P < 0.05), and Pi showed a trend toincrease in the leg muscle (2.8 ± 0.7 to 3.8 ± 0.3 mmHg, P = 0.08). These datademonstrate that TERalb isassociated with PV regulation and that local transcapillary forcesin the leg muscle may favor retention of albumin in the vascular spaceafter exercise. 相似文献
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Association of 70-kilodalton heat-shock cognate proteins with acclimation to cold 总被引:11,自引:3,他引:8 下载免费PDF全文
Neven LG Haskell DW Guy CL Denslow N Klein PA Green LG Silverman A 《Plant physiology》1992,99(4):1362-1369
10.
W Kiess J F Haskell L Lee L A Greenstein B E Miller A L Aarons M M Rechler S P Nissley 《The Journal of biological chemistry》1987,262(26):12745-12751
To better define the biologic function of the type II insulin-like growth factor (IGF) receptor, we raised a blocking antiserum in a rabbit by immunizing with highly purified rat type II IGF receptor. On immunoblots of crude type II receptor preparations, only bands corresponding to the type II IGF receptor were seen with IgG 3637, indicating that the antiserum was specific for the type II receptor. Competitive binding and chemical cross-linking experiments showed that IgG 3637 blocked binding of 125I-IGF-II to the rat type II IGF receptor, but did not block binding of 125I-IGF-I to the type I IGF receptor, nor did IgG 3637 block binding of 125I-insulin to the insulin receptor. In addition, IgG 3637 did not inhibit the binding of 125I-IGF-II to partially purified 150- and 40-kDa IGF carrier proteins from adult and fetal rat serum. L6 myoblasts have both type I and type II IGF receptors. IGF-I was more potent than IGF-II in stimulating N-methyl-alpha-[14C]aminoisobutyric acid uptake, 2-[3H]deoxyglucose uptake, and [3H]leucine incorporation into cellular proteins. IgG 3637 did not stimulate either 2-[3H]deoxyglucose uptake, N-methyl-alpha-[14C]aminoisobutyric acid uptake, or [3H]leucine incorporation into protein when tested alone. Furthermore, IgG 3637 at concentrations sufficient to block type II receptors under conditions of the uptake and incorporation experiments did not cause a shift to the right of the dose-response curve for stimulation of these biologic functions by IGF-II. We conclude that the type II IGF receptor does not mediate IGF stimulation of N-methyl-alpha-[14C]aminoisobutyric acid and 2-[3H]deoxyglucose uptake and protein synthesis in L6 myoblasts; presumably, the type I receptor mediates these biologic responses. The anti-type II receptor antibody inhibited IGF-II degradation in the media by greater than 90%, suggesting that the major degradative pathway for IGF-II in L6 myoblasts utilizes the type II IGF receptor. 相似文献