Wilms' tumour is a paediatric malignancy of the kidneys and is the most common solid tumour found in children. The Wilms' tumour suppressor protein WT1 is mutated in approximately 15% of Wilms' tumours, and is aberrantly expressed in many others. WT1 can manifest both tumour suppressor and oncogenic activities, but the reasons for this are not yet clear. The Wilms' tumour suppressor protein WT1...

Carcinogenesis is a multistep process in which cells accumulate multiple genetic alterations as they progress to a more malignant phenotype. Allelic chromosomal losses as well as mutations of tumor suppressor genes are common genetic events in the development and/or progression of both hereditary and non-hereditary tumors. Recent studies have shown a direct correlation between malignancy and in...

The mechanism by which I-J restrictions were imposed on second-order suppressor cells (Ts2) was analyzed. The induction of Ts2 cells requires presentation of an inducer suppressor factor by a specialized population of factor-presenting cells. The I-J phenotype of this factor-presenting population controls the H-2 restriction of the Ts2 cells. The splenic cells responsible for presenting inducer...

To counteract host antiviral RNA silencing, plant viruses express suppressor proteins that function as pathogenicity enhancers. The genome of the Tomato chlorosis virus (ToCV) (genus Crinivirus, family Closteroviridae) encodes an RNA silencing suppressor, the protein p22, that has been described as having one of the longest lasting local suppressor activities when assayed in Nicotiana benthamia...

The control of proliferation and differentiation by tumor suppressor genes suggests that evolution of divergent tumor suppressor repertoires could influence species' regenerative capacity. To directly test that premise, we humanized the zebrafish p53 pathway by introducing regulatory and coding sequences of the human tumor suppressor ARF into the zebrafish genome. ARF was dormant during develop...

The mechanism of alloantigen-activated spleen cell suppression of mixed lymphocyte reaction (MLR) is explored in this report. Activated murine suppressor spleen cells elaborated a soluble noncytotoxic factor which suppressed MLR responses by 55-95%. Generation of suppressor factor required both in vivo alloantigen sensitization and specific in vitro restimulation. Suppressor factor was not prod...

4-Hydroxy-3-nitrophenyl (NP) derivatized syngeneic spleen cells injected intravenously stimulate maturation of an antigen-binding, idiotype-bearing induction-phase suppressor cell population, as well as an idiotype-binding anti-idiotype-bearing effector-phase suppressor cell population. Both cell types are present simultaneously in the spleen cell population 7-d after their induction. Furthermo...