Einstein Researchers Discover Key to Cell Specialization (Abhishekh Bhattacharya)
As development progresses, many cells become specialized to play particular roles in their respective organs. Often this specialization, which is called differentiation, depends on master regulatory genes that control the expression of a battery of other genes needed to confer specialized properties. The basic Helix-Loop-Helix (bHLH) proteins are a set of master regulators that each function in distinct tissues including muscle, nervous system, fat, etc. Baker and Bhattacharya have used the fruitfly Drosophila melanogaster to understand how bHLH protein function depends on regulation of another set of proteins that dimerize with them. A simple conserved network explains how other proteins define body regions where bHLH proteins can function during specific time windows as master regulators that are able to create specialized cells.
For more information please see: http://www.einsteinmed.org/news/releases/738/einstein-researchers-discover-key-to-cell-specialization/
The Orchestration of Mammalian Tissue Morphogenesis through a Series of Coherent Feed-forward Loops (Qing Xie)
This paper demonstrates that Pax6 and c-Maf orchestrate expression of a- and b/g-crystallin genes through a series of parallel coherent feed-forward loops. This robust expression system generates lens major structural proteins, the crystallins, and, thus, serves as the foundation to form the unique three-dimensional structure, transparency and refractive power of the ocular lens.
For more information please see: http://www.jbc.org/content/286/50/43259.long
DNA methylation changes in murine breast adenocarcinomas allow the identification of candidate genes for human breast carcinogenesis. (Deanna Acosta)
Mamm Genome2011 Apr;22(3-4):249-59. Epub 2011 Mar 4.
Changes in DNA methylation patterns are associated with breast tumorigenesis where they occur at early stages of transformation. Mouse models have been instrumental for the dissection of basic pathways leading to tumorigenesis in a variety of solid tumors. However if murine models for breast tumors exhibit similar DNA methylation changes as observed in human is unknown. This is an important question to address because the validation of murine models for epigenetic analysis will open new possibility to perform studies that would be difficult to carry on with human samples.
Deanna used the HELP assay to map cytosine methylation changes inprimary adenocarcinomas and paired lung metastasesderived from the polyomavirus middle T antigen mouse model. She has shown that breast tumorigenesis in the mouse undergo deregulation of DNA Methylation similar to what observed in human breast tumors. Shepresents amodel in which comparative epigenetic techniques can beused to identify novel candidate genes important for humanbreast tumorigenesis, in both primary and metastatictumors.
For more information please see: http://www.springerlink.com/content/484312n423148047/
Septin 9 isoform expression, localization and epigenetic changes during human and mouse breast cancer progression. (Diana Connolly)
Breast Cancer Res. 2011 Aug 10;13(4):R76.
Septin 9 is a novel oncogene that undergo gene amplification and over expression during breast tumorigenesis. Septin 9 codes for multiple isoform variants which pattern of expression is altered during tumorigenesis. The function of the isoform variants and the mechanisms that lead to their deregulation during breast tumorigenesis is unknown. Diana demonstrated that methylation at one alternative promoter occurs during breast tumorigenesis and leads to the silencing of its corresponding isoform. In addition she presents evidence that Septin 9 isoforms have different cellular localization and may provide different cellular functions, supporting the significance of their alteration of expression observed in breast tumors. Diana's study underlies the importance of studying isoforms variants, a filed largelyunder investigated.
For more information please see: http://breast-cancer-research.com/content/13/4/R76
Discovery of functional gene variants associated with human longevity: opportunities and challenges. (Miook Cho)
PMID: 22156437. 2011. Dec 7. [Epub ahead of print]
Tazearslan*, C., Cho*, M., and Suh,Y. Discovery of functional gene variants associated with human longevity: opportunities and challenges. J Gerontol A Biol Sci Med Sci. * These authors contributed equally to this work
b-catenin-dependent FGF signaling sustains cell survival in the anterior embryonic head by countering Smad4. (Hunki Paek)
Dev. Cell 20: 689-699.
Paek H, Hwang JY, Zukin RS, Hébert JM. (2011). b-catenin-dependent FGF signaling sustains cell survival in the anterior embryonic head by countering Smad4.
This paper describes how multiple extracellular signals interact to regulate the survival of the precursor cells that form the anterior part of the head (including the forebrain) during embryogenesis.