Laboratory of Molecular Biology

About: Laboratory of Molecular Biology is a facility organization based out in Cambridge, Cambridgeshire, United Kingdom. It is known for research contribution in the topics: Gene & RNA. The organization has 19395 authors who have published 24236 publications receiving 2101480 citations.

MicroRNA-155 Functions as an OncomiR in Breast Cancer by Targeting the Suppressor of Cytokine Signaling 1 Gene

Abstract: MicroRNA-155 (miR-155) is overexpressed in many human cancers; however, the mechanisms by which miR-155 functions as a putative oncomiR are largely unknown. Here, we report that the tumor suppressor gene suppressor of cytokine signaling 1 (socs1) is an evolutionarily conserved target of miR-155 in breast cancer cells. We found that mir-155 expression is inversely correlated with socs1 expression in breast cancer cell lines as well as in a subset of primary breast tumors. We also identified a 24A-->G mutation in the miR-155 binding site of the SOCS1 3' untranslated region in a breast tumor that reduced miR-155 repression, implicating a mechanism for miRNA targets to avoid repression. Ectopic expression of miR-155 significantly promoted the proliferation of breast cancer cells, the formation of soft agar foci in vitro, and the development of tumors in nude mice. In breast cancer cells, RNA interference silencing of socs1 recapitulates the oncogenic effects of miR-155, whereas restoration of socs1 expression attenuates the protumorigenesis function of miR-155, suggesting that miR-155 exerts its oncogenic role by negatively regulating socs1. Overexpression of miR-155 in breast cancer cells leads to constitutive activation of signal transducer and activator of transcription 3 (STAT3) through the Janus-activated kinase (JAK) pathway, and stimulation of breast cancer cells by the inflammatory cytokines IFN-gamma and interleukin-6 (IL-6), lipopolysaccharide (LPS), and polyriboinosinic: polyribocytidylic acid [poly(I:C)] significantly upregulates mir-155 expression, suggesting that miR-155 may serve as a bridge between inflammation and cancer. Taken together, our study reveals that miR-155 is an oncomiR in breast cancer and that miR-155 may be a potential target in breast cancer therapy. Cancer Res; 70(8); 3119-27. (C) 2010 AACR.

Subunit structure of chromatin

Abstract: IN the past, the structure of chromatin has remained obscure despite the efforts of many laboratories and seemed far from a simple solution1. It has been known only that chromatin contains a repeating substructure2,3. Recently, however, Kornberg proposed4 that chromatin structure is based on a repeating subunit of 200 base pairs of DNA and two of each of the histones (with the exception of F1 which occurs only once per subunit). Furthermore, he suggested that in chromatin these subunits form a flexibly jointed chain.

Common origins of RNA, protein and lipid precursors in a cyanosulfidic protometabolism

Abstract: A minimal cell can be thought of as comprising informational, compartment-forming and metabolic subsystems. To imagine the abiotic assembly of such an overall system, however, places great demands on hypothetical prebiotic chemistry. The perceived differences and incompatibilities between these subsystems have led to the widely held assumption that one or other subsystem must have preceded the others. Here we experimentally investigate the validity of this assumption by examining the assembly of various biomolecular building blocks from prebiotically plausible intermediates and one-carbon feedstock molecules. We show that precursors of ribonucleotides, amino acids and lipids can all be derived by the reductive homologation of hydrogen cyanide and some of its derivatives, and thus that all the cellular subsystems could have arisen simultaneously through common chemistry. The key reaction steps are driven by ultraviolet light, use hydrogen sulfide as the reductant and can be accelerated by Cu(I)–Cu(II) photoredox cycling. A minimal cell — one that has all the minimum requirements for life — is still a complex entity comprising informational, compartment-forming and metabolic subsystems. Here it is shown that, contrary to previous assumptions, a common prebiotically plausible chemistry can give rise to building blocks for all the subsystems.

Tomato bushy stunt virus at 2.9 A resolution.

Abstract: The polypeptide chain of a TBSV subunit folds into two domains, connected by a hinge, and a flexibly-linked N-terminal arm. Sixty of the 180 N-terminal arms inter-digitate in groups of three, in an unexpected mode of protein association. The remaining 120 arms are not uniquely positioned with respect to the rest of the subunit. RNA is also not uniquely fixed to sites on the major domains.

Polygenic Risk Scores for Prediction of Breast Cancer and Breast Cancer Subtypes

Abstract: Stratification of women according to their risk of breast cancer based on polygenic risk scores (PRSs) could improve screening and prevention strategies. Our aim was to develop PRSs, optimized for prediction of estrogen receptor (ER)-specific disease, from the largest available genome-wide association dataset and to empirically validate the PRSs in prospective studies. The development dataset comprised 94,075 case subjects and 75,017 control subjects of European ancestry from 69 studies, divided into training and validation sets. Samples were genotyped using genome-wide arrays, and single-nucleotide polymorphisms (SNPs) were selected by stepwise regression or lasso penalized regression. The best performing PRSs were validated in an independent test set comprising 11,428 case subjects and 18,323 control subjects from 10 prospective studies and 190,040 women from UK Biobank (3,215 incident breast cancers). For the best PRSs (313 SNPs), the odds ratio for overall disease per 1 standard deviation in ten prospective studies was 1.61 (95%CI: 1.57-1.65) with area under receiver-operator curve (AUC) = 0.630 (95%CI: 0.628-0.651). The lifetime risk of overall breast cancer in the top centile of the PRSs was 32.6%. Compared with women in the middle quintile, those in the highest 1% of risk had 4.37- and 2.78-fold risks, and those in the lowest 1% of risk had 0.16- and 0.27-fold risks, of developing ER-positive and ER-negative disease, respectively. Goodness-of-fit tests indicated that this PRS was well calibrated and predicts disease risk accurately in the tails of the distribution. This PRS is a powerful and reliable predictor of breast cancer risk that may improve breast cancer prevention programs.