Roles of long noncoding RNAs during early development and how their misregulation contributes to disease
X-Chromosome Inactivation, Long Noncoding RNAs, Human Pluripotent Stem Cells, Epigenetics
My lab investigates dosage compensation of the human X-chromosome: how females initiate transcriptional silencing of one X-chromosome and how unbalanced expression from faulty silencing contributes to disease. Female mammals have two X-chromosomes, and one X is randomly chosen for transcriptional silencing in order to equalize the expression of X-linked genes between males (XY) and females (XX). This silencing event, called X-Chromosome Inactivation (XCI), is initiated by the long noncoding RNA XIST, and takes place in the female preimplantation embryo. We are examining how XIST RNA forms the heterochromatic inactive X-chromosome during human development, currently impossible to model, by developing inducible XIST expression systems in somatic cells and human pluripotent stem cells.
X-Chromosome Inactivation (XCI) is one of the best-characterized epigenetic phenomena where long noncoding RNAs are key players that regulate gene expression changes that are inherited after cell division. We also investigate other long noncoding RNAs expressed from the X-chromosome and elsewhere in the genome, to determine their function and mechanism. We are focused on lncRNAs expressed during early human development, specifically in the pluripotent state and BMP4-differentiated cells (to generate trophectoderm-like cells). We use human pluripotent stem cells as a model system to determine how long noncoding RNAs regulate gene expression changes required for normal development. We are investigating the function of human long noncoding RNAs using molecular biology, genetics, microscopy, and bioinformatics.
Human-specific mechanisms of X-Chromosome Inactivation
Our understanding of XCI is mostly from mouse models, yet it’s still unclear how XCI is regulated in humans. The XIST gene, the master regulator of XCI, is well conserved between mice and humans, unlike its neighboring long noncoding RNAs. We seek to determine how XIST RNA cooperates with chromatin modifying complexes to convert the human active X-chromosome into a heterochromatic inactive X.
Genetic analysis of the human X-Inactivation Regulatory Center
The X-Inactivation Center (XIC) contains all the necessary genes for silencing an X-chromosome, and these regions are quite different between mouse and human. We are investigating how this region is regulated during early human development using human pluripotent stem cells to model the preimplantation embryo. Using genome editing technologies (TALENs and CRISPRs), we are introducing mutations for investigating how these long noncoding RNA genes function.
Novel long noncoding RNAs important for early human development
Next-generation sequencing experiments have found that there are thousands of long noncoding RNAs exhibiting cell and tissue-specific expression, yet the function of these transcripts is largely unknown. We are examining the transcriptional profile of human female pluripotent stem cells and in vitro differentiated cells to determine the predominant transcripts expressed in these cell types, and determining how these transcripts function in vivo.
Lessing D, Anguera MC, Lee JT. X chromosome inactivation and epigenetic responses to cellular reprogramming. Annu Rev Genomics Hum Genet. 14: 85-110, 2013.Anguera Montserrat C, Sadreyev Ruslan, Zhang Zhaoqing, Szanto Attila, Payer Bernhard, Sheridan Steven D, Kwok Showming, Haggarty Stephen J, Sur Mriganka, Alvarez Jason, Gimelbrant Alexander, Mitalipova Maisam, Kirby James E, Lee Jeannie T Molecular signatures of human induced pluripotent stem cells highlight sex differences and cancer genes. Cell stem cell 11: 75-90, 2012.Anguera Montserrat C, Ma Weiyuan, Clift Danielle, Namekawa Satoshi, Kelleher Raymond J, Lee Jeannie T Tsx produces a long noncoding RNA and has general functions in the germline, stem cells, and brain. PLoS genetics 7: e1002248, 2011.Kim Daniel H, Jeon Yesu, Anguera Montserrat C, Lee Jeannie T X-chromosome epigenetic reprogramming in pluripotent stem cells via noncoding genes. Seminars in cell & developmental biology 22: 336-42, 2011.Field Martha S, Anguera Montserrat C, Page Rodney, Stover Patrick J 5,10-Methenyltetrahydrofolate synthetase activity is increased in tumors and modifies the efficacy of antipurine LY309887. Archives of biochemistry and biophysics 481: 145-50, 2009.Anguera Montserrat C, Liu Matthew, Avruch Joseph, Lee Jeannie T Characterization of two Mst1-deficient mouse models. Developmental dynamics : an official publication of the American Association of Anatomists 237: 3424-34, 2008.Anguera Montserrat C, Stover Patrick J Methenyltetrahydrofolate synthetase is a high-affinity catecholamine-binding protein. Archives of biochemistry and biophysics 455: 175-87, 2006.Anguera Montserrat C, Field Martha S, Perry Cheryll, Ghandour Haifa, Chiang En-Pei, Selhub Jacob, Shane Barry, Stover Patrick J Regulation of folate-mediated one-carbon metabolism by 10-formyltetrahydrofolate dehydrogenase. The Journal of biological chemistry 281: 18335-42, 2006.Anguera M C, Sun B K, Xu N, Lee J T X-chromosome kiss and tell: how the Xs go their separate ways. Cold Spring Harbor symposia on quantitative biology 71: 429-37, 2006.Anguera Montserrat C, Liu Xiaowen, Stover Patrick J Cloning, expression, and purification of 5,10-methenyltetrahydrofolate synthetase from Mus musculus. Protein expression and purification 35: 276-83, 2004.