Dissecting DISC1 function through protein-protein interactions
BIOCHEMICAL SOCIETY TRANSACTIONS
Authors: Brandon, N. J.
Abstract
Disrupted in schizophrenia 1 (DISC1) is emerging in the eyes of many as the most promising candidate of all the schizophrenia risk genes. This viewpoint is derived from the combination of genetic, clinical, imaging and rapidly advancing cell biology data around this gene. All of these areas have been reviewed extensively recently and this review will point you towards some of these excellent papers. My own personal view of the potential importance of DISC1 was echoed in a recent review which suggested that DISC1 may be a 'Rosetta Stone' for schizophrenia research [Ross, Margolis, Reading, Pletnikov and Coyle (2006) Neuron 52, 139-153]. Our own efforts to try to understand the function of DISC1 were through identification of its protein-binding partners. Through an extensive Y2H (yeast two-hybrid) and bioinformatics effort we generated the 'DISC1-Interactome', a comprehensive network of protein-protein interactions around DISC1. In two excellent industry-academia collaborations we focused on two main interacting partners: Ndel1 (nudE nuclear distribution gene E homologue-like 1), an enigmatic protein which may have diverse functions as both a cysteine protease and a key centrosomal structural protein; and PDE4B. a cAMP-specific phosphodiestefase. I will review the work around these two protein complexes in detail.
Comparative effects of diet and carcinogen on microRNA expression in the stem cell niche of the mouse colonic crypt
BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR BASIS OF DISEASE
Authors: Shah, Manasvi S.; Kim, Eunjoo; Davidson, Laurie A.; Knight, Jason M.; Zoh, Roger S.; Goldsby, Jennifer S.; Callaway, Evelyn S.; Zhou, Beyian; Ivanov, Ivan; Chapkin, Robert S.
Abstract
There is mounting evidence that noncoding microRNAs (miRNA) are modulated by select chemoprotective dietary agents. For example, recently we demonstrated that the unique combination of dietary fish oil (containing n - 3 fatty acids) plus pectin (fermented to butyrate in the colon) (FPA) up-regulates a subset of putative tumor suppressor miRNAs in intestinal mucosa, and down-regulates their predicted target genes following carcinogen exposure as compared to control (corn oil plus cellulose (CCA)) diet. To further elucidate the biological effects of diet and carcinogen modulated miR's in the colon, we verified that miR-26b and miR-203 directly target PDE4B and TCF4, respectively. Since perturbations in adult stem cell dynamics are generally believed to represent an early step in colon tumorigenesis and to better understand how the colonic stem cell population responds to environmental factors such as diet and carcinogen, we additionally determined the effects of the chemoprotective FPA diet on miRNAs and mRNAs in colonic stem cells obtained from Lgr5-EGFP-IRES-creER(T2) knock-in mice. Following global miRNA profiling, 26 miRNAs (P < 0.05) were differentially expressed in Lgr51(high) stem cells as compared to Lgr5(negative) differentiated cells. FPA treatment up-regulated miR-19b, miR-26b and miR-203 expression as compared to CCA specifically in Lgr5(high) cells. In contrast, in Lgr5(negative) cells, only miR-19b and its indirect target PTK2B were modulated by the FPA diet. These data indicate for the first time that select dietary cues can impact stem cell regulatory networks, in part, by modulating the steady-state levels of miRNAs. To our knowledge, this is the first study to utilize Lgr5 reporter mice to determine the impact of diet and carcinogen on miRNA expression in colonic stem cells and their progeny. (C) 2015 Elsevier B.V. All rights reserved.