A change of a universally conserved leucine to valine in the DNA‐binding domain of the GATA factor AreA results in inability to activate some AreA‐dependent promoters, including that of the uapA gene encoding a specific urate–xanthine permease. Some other AreA‐ dependent promoters become able to function more efficiently than in the wild‐type context. A methionine in the same position results in a less extreme, but opposite effect. Suppressors of the AreA(Val) mutation mapping in the uapA promoter show that the nature of the base in the first position of an HGATAR (where H stands for A, T or C) sequence determines the relative affinity of the promoter for the wild‐type and mutant forms of AreA. In vitro binding studies of wild‐type and mutant AreA proteins are completely consistent with the phenotypes in vivo. Molecular models of the wild‐type and mutant AreA–DNA complexes derived from the atomic coordinates of the GATA‐1–AGATAA complex account both for the phenotypes observed in vivo and the binding differences observed in vitro. Our work extends the consensus of physiologically relevant binding sites from WGATAR to HGATAR, and provides a rationale for the almost universal evolutionary conservation of leucine at the seventh position of the Zn finger of GATA factors. This work shows inter alia that the sequence CGATAGagAGATAA, comprising two almost adjacent AreA‐binding sites, is sufficient to ensure activation of transcription of the uapA gene.

No abstract

The reported high risk of BC after childhood Hodgkin's disease treatment seems to be due not only to a higher radiation dose to the breasts, but also to a specific susceptibility.

Connexins are structurally related transmembrane proteins that assemble to form gap junction channels involved in the mediation of intercellular communication. It has been shown that the intracellular tail of connexin43 (Cx43) interacts with tubulin and microtubules with putative impacts on its own intracellular trafficking, its activity in channel communication, and its interference with specific growth factor signal transduction cascades. We demonstrate here that the microtubule binding of Cx43 is mainly driven by a short region of 26 amino acid residues located within the intracellular tail of Cx43. The nuclear magnetic resonance structural analysis of a peptide (K26D) corresponding to this region shows that this peptide is unstructured when free in solution and adopts a helix conformation upon binding with tubulin. In addition, the resulting K26D-tubulin molecular complex defines a new structural organization that could be shared by other microtubule partners. Interestingly, the K26D-tubulin interaction is prevented by the phosphorylation of K26D at a src kinase specific site. Altogether, the results elucidate the mechanism of the interaction of Cx43 with the microtubule cytoskeleton and propose a pathway for understanding the microtubule-dependent regulation of Cx43 gap junctional communications and the involvement of Cx43 in TGF-β signal transduction.

The aim of our study was to quantify the risk of second malignant neoplasms (SMNs) among long-term survivors of neuroblastoma and to study the influence of treatment on this risk. We studied data from 544 5-year survival patients diagnosed with neuroblastoma before age 16 years at 8 French and British treatment centres from 1948 to 1986. After an average follow-up of 15 years (range, 5-38 years), 12 children developed a total of 13 SMNs, whereas 1.19 were expected from general population rates. Among these SMNs, there were 5 thyroid and 3 breast cancers. Increases of the risks of SMN were observed with time since neuroblastoma diagnosis and attained age. In a multivariate analysis, the relative risk of SMN associated with radiotherapy was 4.3 (95% CI 0.8 -78), whereas no increased risk of SMN was associated with the administration of chemotherapy as a whole (RR ‫؍‬ 0.4, 95% CI 0.1-1.9). Young children treated for a neuroblastoma have significantly increased risks of SMN over 3 decades of follow-up. Radiotherapy treatment was found to be an important risk factor for developing SMNs, whereas no effect of chemotherapy was evidenced. Although our findings reflect the late effects of past therapeutic modalities, they underscore the importance of long-term surveillance of young children treated for a neuroblastoma. For these patients, many more years of follow-up are required to appreciate their overall risks of treatment-related SMNs. © 2003 Wiley-Liss, Inc. Key words: second malignant neoplasm; radiation; childhood cancer; neuroblastomaNeuroblastoma is one of the most common solid tumors in childhood. Conventional treatments of this neoplasm integrate surgery, radiation therapy, combination chemotherapy and more recently, high-dose chemotherapy followed by bone marrow transplantation. Treatment options are related to age of the child, location and biology of the tumor and stage of disease.After successful treatment of malignant diseases in childhood, the problem of long-term complications came to the fore. General evaluation of the long-term carcinogenic risks induced by radiotherapy, chemotherapy and their association after treatment for childhood cancer, have already been published. 1-5 However, cohort studies dealing with the very long-term incidence of second malignant neoplams (SMNs) in children initially treated for a neuroblastoma are sparse. 1,3,[5][6][7][8][9][10] This rarity is due in part to the low survival rates from neuroblastoma, in particular for the patients treated in past decades before the introduction of new therapeutic approaches. Therefore, little is known about the factors that determine the long-term risk of SMN following this cancer.In our current study, we investigated the role of radiotherapy and chemotherapy given for the neuroblastoma treatment on the risk of subsequent SMN development for 544 5-year survival patients treated for a neuroblastoma from 1948 -1986 at 8 hospital centres in France and Great Britain. Our study, including about 1/3 of 25-year survival patients, enabled us to a...

Neocarzinostatin is the most studied member of the enediyne-chromoprotein family, and is clinically used as an antitumoral agent. Neocarzinostatin could be a promising drug delivery vehicle if new binding specificities could be conferred to its protein scaffold. We used in vitro evolution methods to demonstrate that this approach is feasible. We created large libraries containing between 1.7 x 10(8) and 1.4 x 10(9) independent clones, where up to 13 side chains pointing toward the binding crevice were randomly substituted. We then used phage display to select variants that bind to a model ligand (testosterone) which is unrelated to the natural ligand of neocarzinostatin. Several different binders were selected from each library. The corresponding proteins were expressed in Escherichia coli and their affinities and specificities were characterized in detail. K(D) values of about 20 nM were obtained for streptavidin-bound testosterone. The K(D) of selected proteins for free soluble testosterone are between 7 and 55 microM and therefore higher than the K(D) for streptavidin-bound testosterone. The spacer and streptavidin used during selection contributed to the high affinity of the selected binders for the target. Binding studies of 15 different steroids related to testosterone allowed us to determine that C3, 4, 5, 6, and 7 on cycles A and B and the conjugated 3 oxo group of the steroid molecule were essential for molecular recognition. Other testosterone analogues substituted on C1, 2, 9, 11, 15, and 17 were not discriminated from testosterone. These results demonstrate that the binding specificity of this protein family can be extended to compounds that are completely unrelated to the natural enediyne chromophore family. This type of highly expressed, stable proteins with tailored binding properties have a wide potential range of applications.

No abstract

The incidence of thyroid cancer has increased in eastern Europe since the Chernobyl nuclear power plant accident. Although the radioactive fallout was much less severe and the thyroid radiation dose was much lower in France, a case-control study was initiated in eastern France. The present study included 633 young women who were diagnosed with differentiated thyroid cancer before 35 years of age between 2002 and 2006 and matched with 677 controls. Face-to-face interviews were conducted from 2005 to 2010. Odds ratios were calculated using conditional logistic regressions and were reported in the total group and by histopathological type of cancer ("only papillary" and "excluding microcarcinomas"). The risk of thyroid cancer was higher in women who had a higher number of pregnancies, used a lactation suppressant, or had early menarche. Conversely, breastfeeding, oral contraceptive use, and late age at first pregnancy were associated with a lower risk of thyroid cancer. No association was observed between thyroid cancer and having irregular menstrual cycle, undergoing treatment for menstrual cycle regularity shortly after menarche, having a cessation of menstruation, use of another contraceptive, history of miscarriage or abortion for the first pregnancy, or having had gestational diabetes. This study confirms the role of hormonal and reproductive factors in thyroid cancer, and our results support the fact that exposure to estrogens increases thyroid cancer risk.