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Katherine Bianco, M.D.
Ob/Gyn Fellow

I am currently pursuing sub-specialty training in a combined fellowship in Maternal-Fetal-Medicine and Human Genetics. As part of my training I am spending a year in the laboratory working on a project to address imprinting defects and their relation to congenital anomalies as a result of Assisted Reproductive Techniques (ART). The primary objective of this study is to determine whether there is a disruption in the methylation of known imprinted genes in fetuses conceived by ART. This work has broad relevance to both basic and translational biologic questions as recent case reports of imprinting disorders and embryo culture studies in animal models suggest that imprinting may be altered by embryo culture and/or ART associated procedures.

  • Bianco, K, Zhou, Y, Romero, R, Fisher SE. Preterm Labor In The Context Of Chorioamnionitis Is Associated With Decreased Cytotrophoblast L-selectin Expression. Biology of Reproduction. Submit.
  • Bianco K, Arici, A, Duleba A, Dakkas D, Taylor HE. Elevated Estradiol levels in oocytes donation do not impair ART outcomes for recipients. Fertility & Sterility. Submit.

James Byrne, Ph.D.
Assistant Professor, UCLA

Embryonic stem cells (ESCs) can proliferate indefinitely, maintain an undifferentiated pluripotent state and differentiate into any cell type.  The ability of ESCs to differentiate into any cell type means we may be able to utilize these cells to cure or alleviate the symptoms of many degenerative diseases.  However, allogenic human ESCs (ESCs derived from spare IVF embryos) are genetically divergent from the host/patient, this means that transplantation of allogenic ESC-derived cell-types into a patient (without immunosuppressive drugs) will incite an immune response and result in the rejection of the transplanted ESCs.  A solution to the immune rejection problem would be to generate isogenic ESCs from somatic cell nuclear transfer (SCNT) embryos derived from the patients own cells, a concept commonly referred to as "therapeutic cloning".  However, the feasibility of human therapeutic cloning is severely limited by both the low blastocyst production efficiency observed following human SCNT and the fact that to date, no primate SCNT ESC line has been produced.  Recently, in collaboration with Dr. Shoukhrat Mitalipov, I have pioneered a number of improvements to the SCNT procedure which have resulted in a significant increase in the efficiency of SCNT blastocyst production in the rhesus monkey and I have derived two rhesus SCNT ESC lines.  My current goals are to investigate if the therapeutic cloning protocols I have successfully used in the non-human primate will work with human oocytes, to understand the underlying mechanisms of SCNT-based reprogramming and to develop basic research and clinical applications based on the SCNT-reprogrammed cell lines.

  • Byrne, J. A., Simonsson, S. and Gurdon, J. B. (2002).  From intestine to muscle: nuclear reprogramming through defective cloned embryos.  Proceedings of the National Academy of Sciences. 99(9):6059-6063.
  • Byrne, J. A. and Gurdon, J. B. (2002).  Commentary on human cloning. Differentiation. 69:154-157.
  • Gurdon, J. B. and Byrne, J. A. (2002).  The history of cloning. Ethical eye: cloning. Council of Europe Publishing. ISBN: 92-971-4702-7.
  • Gurdon, J. B. and Byrne, J. A. (2002). Chapter 14: Cloning of Amphibians. Principles of Cloning. Editors: Cibelli, J., Lanza, R. P., Campbell, K. H. S. and West, M. D.  ISBN: 0-12-174597-X.
  • Byrne, J. A., Simonsson, S., Western, P. S. and Gurdon, J. B. (2003).  Nuclei of adult mammalian somatic cells are directly reprogrammed to Oct-4 stem cell gene expression by amphibian oocytes.  Current Biology. 13(14):1206-1213.
  • Gurdon, J. B., Byrne, J. A. and Simonsson, S. (2003).  Nuclear reprogramming and stem cell creation.  Proceedings of the National Academy of Sciences. Colloquium. August 14, 2003. 10.1073/pnas.1834207100.
  • Gurdon, J. B. and Byrne, J. A. (2003).  The first half-century of nuclear transplantation.  Proceedings of the National Academy of Sciences.  100(14):8048-8052.
  • Gurdon, J. B., Byrne, J. A. and Simonsson, S. (2005).  Nuclear reprogramming by Xenopus oocytes. Novartis Found Symp. 265:129-36.
  • Byrne, J. A., Mitalipov, S. M. and Wolf, D.P. (2006). Current Progress with Primate Embryonic Stem Cells. Current Stem Cell Research & Therapy. 1:127-138.
  • Mitalipov, S. M., Kuo, H. C., Byrne, J. A., Fujimoto, A, Clepper, L, Meisner, L. F., Johnson, J., Zeir, R and Wolf, D. P. (2006). Isolation and characterization of novel rhesus monkey embryonic stem cell lines. Stem Cells. 24: 2177-2186.
  • Byrne, J. A., Mitalipov, S. M., Clepper, L. and Wolf, D. P. (2006). Transcriptional profiling of rhesus monkey embryonic stem cells. Biology of Reproduction. 75: 908-915.
  • Sugihara, K., Sugiyama, D., Byrne, J., Wolf, D., Lowitz, K., Kobayashi, Y., Kabir-Salmani, M., Nadano, D., Aoki, D., Nozawa, S., Nakayama, J., Mustelin, T., Ruoslahti, E., Yamaguchi, N., and Fukuda, M. (2007).  Trophoblast cell activation by trophinin ligation is implicated in human embryo implantation. Proceedings of the National Academy of Sciences. 104:3799-3804.
  • Mitalipov, S. M., Zhou, Q., Byrne, J. A., Ji, W. Z., Norgren, R. B. and Wolf, D. P. (2007).  Reprogramming following somatic cell nuclear transfer in primates is dependent upon nuclear remodeling.  Human Reproduction. June 11; [Epub ahead of print]
Michael Castillo, M.D.

Amander Clark, Ph.D
Assistant Professor, UCLA

Molecular Regulation of Human Germ Cell and Stem Cell Fate Germ cells are absolutely essential for fertility. Abnormal germ cell development results in abnormal sperm production in men, premature ovarian failure in women, abnormal embryogenesis or even gonadal tumors. However, the molecular events that are associated with these germ cell-specific pathologies are almost completely unknown due to the lack of a malleable human genome-based model system.

To solve this problem, we have been working towards building an in vitro cell-based model using human embryonic stem cells (hESCs) and differentiating cells of the germ cell lineage in vitro [3]. Using this model we can begin to explore some of the key molecular and cellular events in human fetal germ cell and stem cell biology [4,5]. In particular, the molecular signals that program germ cell fate, enabling the transition from an embryonic germ cell to an adult germ-line stem cell are almost completely unknown. Our research has shown that there is a switch in the regulation of genes associated with pluripotency during this transition to an adult germ-line stem cell, and that maintenance of the pluripotency program in adult germ cells is associated with the formation of germ cell tumors. Using hESCs and differentiating cells of the human germ cell lineage in vitro, we can begin to modulate this pluripotency-associated program and address its specific function and balance in regulating germ cell fate and tumor formation.

Selected Publications
  • Clark, AT (2006) Establishment and Differentiation of Human Embryonic Stem Cell-Derived Germ Cells. Reproduction suppl (in press).
  • Clark, AT & Pera, RA (2006) Modeling Human Germ Cell Formation with Embryonic Stem Cells. Regenerative Medicine 1:85-93
  • Clark, A.T. Bodnar, M., Fox, M., Rodriguez, R.T., Abeyta, M.J., Firpo, M.T., Reijo-Pera, R.A. (2004) Differentiation of the Human Germ Cell Lineage from Embryonic Stem Cells. Human Molecular Genetics 13(7):727-739.
  • Ezeh, U, Turek, PJ, Reijo Pera, RA, Clark, AT (2005) Human Pluripotent Stem Cell Genes NANOG, STELLAR and GDF3 are expressed in both Seminoma and Breast Cancer. Cancer 104: 2255-2265.
  • Clark, A.T. Rodriguez, R.T., Abeyta, M.J., Firpo, M.T., Reijo-Pera, R.A. (2004) Chromosome 12p13.1, a hot-spot for Teratocarcinoma, Encodes Three Genes Expressed in Pluripotent Cells with Remarkable Evolutionary Divergence from Humans to Mice Stem Cells 22(2) 169-179.

Ucheh Ezeh, M.D.

Reproductive Endocrinology and Infertility Clinical Fellow

Molecular Basis of Culture Media for Human Embryonic Stem Propagation Human embryonic stem cells (hESCs), which are used for transplantation therapy and tissue engineering, require an unlimited source of undifferentiated hESCs that can renew without contact to any animal sources. Yet little is known about factors that determine hESCs pluripotency and much of the U.S federally registered hESC lines were derived in cultures incorporating mouse embryo fibroblast feeders and other animal products.

The focus of my research is to define factors in the culture media that are important for support and propagation of hESCs, thereby enabling the development of culture media devoid of animal-derived products.

Selected publications
  • Uche I. Ezeh, Paul J. Turek, Renee A. Reijo Pera, Amander T. Clark. Human embryonic stem cell genes OCT4, NANOG, STELLAR, and GDF3 are expressed in both seminoma and breast carcinoma. Cancer, 2005; 104:2255-65.
  • Ezeh, UIO, Moore, HDM and Cooke, ID, The correlation of testicular pathology and sperm extraction in azoospermic men with ejaculated spermatids detected by immunofluorescent localization. Hum Reprod, 1999; 13:3061-5.
  • Ezeh, UIO, Moore HDM and Cooke ID, Correlation of testicular perm extraction with biophysical, endocrine and morphological profiles in men with azoospermia due to gonadal failure. Human Reproduction 1998; 13: 3066-74.
  • Ezeh, UIO, Moore, HDM and Cooke, ID, A prospective study of multiple needle biopsies versus a single open biopsy for testicular sperm extraction in men with non-obstructive azoospermia. Human Reproduction, 1998; 13: 3075-80.
  • Ezeh UIO, et al. Morbidity and cost-effective analysis of outpatient analgesia versus general anaesthesia for sperm extraction in men with azoospermia due to defects in spermatogenesis. Hum Reprod 1999; 14:321-8.
  • Ezeh, UIO, Taub N, Moore HDM and Cooke ID, Establishment of predictive variables associated with testicular sperm retrieval in men with nonobstructive azoospermia. Hum Reprod 1999; 14: 1005-12.
  • Ezeh UIO, Modebe O, Is fertility different in adult males with sickle cell trait? Human Biology, 1996; 68:55-62.
  • Modebe O and Ezeh UIO, The effect of age on testicular function in adult males with sickle cell anaemia. Fertility Sterility, 1995; 63: 907-12.
  • Ezeh UIO, Martin J. et al., Local anaesthetics on Filshie clips for post-operative pain relief: A randomized double-blind controlled trial. The Lancet, 1995; 346: 82-5.

Mark Fox, Ph.D.

Assistant Research Geneticist

My research interests center on the study of stem cells and the formation of cell lineages. Most of the work to date by other laboratories has concentrated on two aspects of manipulating embryonic stem cell differentiation, namely identifying pathways of signal transduction that induce differentiation, and the control of transcription/transcription factors that dictate gene expression of cell lineage allocation. However, for stem cells to orchestrate the generation, maintenance and renewal of tissue, the process of development must rely on additional regulatory mechanisms that exist after a gene is transcribed. The mechanisms by which RNA translation ultimately occurs have so far been overlooked. This area of control is complex and involves several important cellular pathways including mRNA turnover and post-translational control of proteins that regulate this mRNA turnover. Therefore within stem cell biology important cellular decisions are imposed, I believe, by protein interactions between conserved RNA binding proteins and the RNA's that they regulate. I have made significant advances in understanding how Protein-RNA complexes, and the modifications of these interactions, regulate the differentiation of stem cells.

  • Cvoro, A., Tzagarakis-Foster, C., Tatomer, D., Paruthiyil, S., Fox, M., Leitman, D. (2006) Distinct roles of Unliganded and Liganded Estrogen Receptors in Transcriptional Repression. Molecular Cell. (In Press)
  • Fox, M., Reijo Pera, R.A and Clark, A.T (2006) The DAZ gene family and human germ cell development from embryonic stem cells. In The Sperm Cell: Production, Maturation, Fertilization, Regeneration. Cambridge University Press.
  • Urano, J., Fox, M., and Reijo Pera, R.A., (2005) Interaction of the Conserved Meiotic Regulators, BOULE (BOL) and PUMILIO-2 (PUM2). Molecular Reproduction and Development 71(3): 290-298
  • Fox, M., Urano, J., and Reijo Pera, R.A., (2005) Identification and Characterization of RNA Sequences to which Human PUMILIO-2 (PUM2) and Deleted in Azoospermia-Like (DAZL) Bind. Genomics 85(1): 92-105
  • Clark, A.T., Bodnar, M.S., Fox, M., Rodriquez, R.T., Abeyta, M.J., Firpo, M.T., Reijo Pera, R.A., (2004) Spontaneous differentiation of germ cells from human embryonic stem cell in vitro. Human Molecular Genetics 13(7): 727-739
  • Fox, M., Ares, X.V., Turek, P.J., Haqq, C., Reijo Pera, R.A (2003) Feasibility of Global Gene Expression Analysis in Testicular Biopsies From Infertile Men. Molecular Reproduction and Development. Molecular Reproduction and Development 66: 403-421
  • Martinez-Calvillo, S., S. Yan, Nguyen D, Fox M, Stuart K,. (2003). Transcription of Leishmania major Friedlin chromosome 1 initiates in both directions within a single region. Molecular Cell 11(5): 1291-9
  • Moore, F.L., Jaruzelska, J. Fox, M., Urano, J., Firpo, M.T., Turek, P.J., Dorfman, D.M., Reijo Pera, R.A., (2003) Human Pumilio-2 is expressed in embryonic stem cells and germ cells and interacts with DAZ (Deleted in AZoospermia) and DAZ-like proteins. Proc Natl Acad Sci U S A 100(2): 538-43
  • Fox, M., Reijo, R., (2001) Male Infertility, Genetic Analysis of the DAZ Genes on the Human Y Chromosome and Genetic Analysis of DNA Repair . Molecular and Cellular Endocrinology, 184, 41-49
  • Martenez-Calvillo, S., Sunkin, SM., Yan, S., Fox, M., Stuart, K., Myler, PJ (2001) Genomic organization and functional characterization of the Leishmania major Friedlin ribosomal RNA gene locus. Molecular and Biochemical Parasitology, 116: 147-157
  • Shiels, B; Fox, M; McKellar, S; Kinnaird, J; Swan, D (2000). An upstream element of the TamS1 gene is a site of DNA-protein interactions during differentiation to the merozoite in Theileria annulata. Journal of Cell Science, 113 (12):2243-52
  • Knight, P., Williamson, S., Brown, D., Kinnaird, J., Fox, M., Khalid, H., Hall, R., Tait, A. (1999) The Theileria annulata sporozoite and macroschizont polypeptide encoded by the spm1 gene shares phenylalanine-glycine motifs with nuclear pore proteins. Molecular and Biochemical Parasitology, 100: 135-140
  • Yan, S; Lodes, MJ; Fox, M; Myler, PJ; Stuart, K. (1999) Characterization of the Leishmania donovani ribosomal RNA promoter. Molecular and Biochemical Parasitology, 103(2):197-210
  • Shiels, B., Swan, D., McKellar, S., Aslam, N., Dando, C., Fox, M., Ben-Miled, L., and Kinnaird, J., (1998) Directing differentiation in Theileria annulata: old methods and new possibilities for control of apicomplexan parasites. International Journal of Parasitiology. 28, 1659-1670


Juanito Meneses, B.A.

My current research involves characterizing recently established human embryonic stem cells lines. In addition, my research encompasses the creation of various transgenic mice by pronuclear injection and knockout mice by injection of mouse blastocysts with stem cells possessing disrupted genes. In the past, I derived 2 human stem cell lines (HSF1 & HSF6) consistent with the Presidential Statement of August 9, 2001.

Selected Publications
  • Pfendler, Kristina C., Catuar, Carmina S., Meneses, Juanito J., Pedersen, Roger A. Overexpression of Nodal Promotes Diffrerentiation of Mouse Embryonic Stem Cells into Mesoderm and Endoderm at the Expense of Neuroectoderm FormationStem Cells and Development.2005 April, 14 (2) 162-72
  • Li, L., Salido, E., Zhou, Y.,Bhattacharyya, S., Yannone, S.M. Dunn, E., Meneses, J., Feeney, A.J., Cowan, M.J. Targeted disruption of the Artemis murine counterpart results in SCID and defective V(D)J recommendation that is partially corrected by bone marrow transplantation. Journal of Immunology 2005 Feb. 15; 174(4): 2420-8.
  • Wang, Z., Zhai, W., Richardson, J.A., Olson, E.N., Meneses, J.J., Firpo, M.T., Kang, C., Skarnes, W.C., Tijan, R. Polybromo protein BAF180 functions in mammalian cardiac chamber maturation. Genes and Development 2004, Dec. 15; 18(24): 3103-16
  • Bodnar, Megan S., Meneses, Juanito J., Rodriguez, Ryan T., Firpo, Meri T. Propagation and Maintenance of Undifferentiated Human Embryonic Stem Cells. Stem Cells and Development June 2004, Vol. 13, No. 3:243-253
  • Boucher, D.M, Schaffer, M., Deissler, K., Moore, C.A., Gold, J.D., Burdsal, C.A., Meneses, J.J., Pedersen, R.A., Blum, M. Goosecoid expression represses Brachyury in embryonic stem cells and affects craniofacial development in chimeric mice. International Journal of Developmental biology 2000 Apr, 44(3): 279-88.

Frederick Moore, Ph.D.

I began my tenure in graduate school in 1997 at UCSF, and subsequently joined Dr. Reijo Pera's lab as her first graduate student in 1998. My thesis focused on understanding the role of the DAZ gene family in human germ cell development. At this early stage in the field of human reproductive genetics, we discovered six genes that made proteins which interacted with the DAZ protein. At the time, deletions of the DAZ genes on the Y chromosome were the most characterized genetic cause of infertility in humans. Interestingly, many of the genes we discovered were expressed in germ cells and embryonic stem cells. These findings allowed for the creation of molecular models to understand how germ cells and embryonic stems are regulated in humans. I completed my doctorate degree in 2002.

During that time period, I co-founded a nonprofit organization called Brothers Building Diversity in the Sciences (BBDS). The mission of BBDS is to utilize science as a platform to empower underrepresented minority students to pursue careers available with a science background. My work with BBDS eventually lead me to co-edit and publish a book titled Finding Your North: Self-Help Strategies for Science-Related Careers (FYN). This book is designed to help students discover their purpose in life, while using science as the framework for the discussion. I'm currently the co-founder and Principal of PotentSci LLC, which is a company that focuses on educational consulting and book publishing in the science space. You can learn more about FYN and BBDS at: &

Selected Publications
  • Moore, F.L., Jaruzelska,J., Dorfman, D.M., Reijo-Pera, R.A., "Identification of a Novel Gene, DZIP (DAZ Interacting Protein), that Encodes a Protein that Interacts with DAZ (Deleted in AZoospermia) and is Expressed in Embryonic Stem Cells and Germ Cells", Genomics 83/5, 834-843 (2004).
  • Moore,F.L., Jaruzelska,J., Fox, M.S., Urano, J., Firpo, M.T., Turek, P.J. Dorfman, D.M., Reijo-Pera, R.A., "A Human Homologue of Drosophila Pumilio is Expressed in Embryonic Stem Cells and Germ Cells and Interacts with DAZ (Deleted in AZoospermia) Protein", Proceedings in the National Academy of Sciences, 100(2), 538-543 (2003).
  • Xu,E., Moore, F.L., Reijo-Pera,R.A., "A Gene Family Required for Human Germ Cell Development Evolved from an Ancient Meiotic Gene Conserved in all Metazoans", Proceedings in the National Academy of Sciences 98, 7414-7419 (2001).
  • Moore, F.L. and Reijo-Pera, R.A., "Male Sperm Motility Dictated by Mother's mtDNA", American Journal of Human Genetics 67, 543-548 (2000).

Nick Salmon, Ph.D.

Postdoctoral Fellow

I am currently using genetic approaches, such as gene trapping and conditional gene targeting to study the process of germ cell development in mice. This project has the potential to determine key genes involved in mammalian germ cell development and uncover candidate genes for human infertility. This research makes use of many timely advances in mouse genetics such as the propagation of large scale gene trap resources (IGTC), a publicly available genome-wide 129Sv BAC library resource (Sanger Centre) and recent advances in the construction of conditional targeting vectors, such as recombineering.

  • Salmon, N. A., Handyside, A. H., and Joyce, I. M. (2004). Oocyte regulation of anti-Mullerian hormone expression in granulosa cells during ovarian follicle development in mice. Developmental Biology 266, 201-8.
  • Salmon, N. A., Handyside, A. H., and Joyce, I. M. (2005). Expression of Sox8, Sf1, Gata4, Wt1, Dax1, and Fog2 in the mouse ovarian follicle: implications for the regulation of Amh expression. Molecular Reproduction and Development 70, 271-7.

Shai Shefi, M.D.
Andrology Fellow

As an Andrology Fellow in the Urology department at UCSF, I've been able to combine clinical material with accumulated knowledge and cutting edge stem cells technologies for my research goals in the Reijo-Pera lab. My study involves the ability to grow human type A spermatogonia in vitro, and then to induce differentiation and to genetically manipulate these cells. In addition, I'm also interested in utilizing human seminoma to achieve similar goals and to investigate the association between male infertility and testicular cancer.

  • Shefi S, Haskel Y: Simultaneous bilateral testicular torsion in an adult. J. Urol. 159: 206, 1998.
  • Shefi S, Mor Y, Dotan ZA, Ramon J: Traumatic testicular dislocation: A case report and review of published reports. Urology 54: 744, 1999.
  • Dotan ZA, Mor Y, Olchovski D, Aviel-Ronen S, Engelberg S, Pinthus JH, Shefi S, Leibovitch I, Ramon J: Solitary fibrous tumor presenting as Perirenal Mass associated with hypoglycemia. J. Urol. 162: 2087, 1999.
  • Shefi S, Mor Y, Fridman E, Neumann Y, Heyman Z, Dotan ZA, Ramon J: Paratesticular yolk sac tumor in a child.J. Urol. 164: 1708, 2000.
  • Raviv G, Pinthus JH, Shefi S, Mor Y, Kaufman-Francis K, Levron J, Weissenberg R, Ramon J, Madgar I: Effects of intravesical chemotherapy and immunotherapy on semen analysis. Urology 65: 765-7, 2005.
  • Misell LM, Holochwost D, Boban D, Santi N, Shefi S, Hellerstein MK, Turek PJ: A Stable Isotope and Mass Spectrometric Method for Measuring Human Spermatogenesis Kinetics in vivo. J. Urol. 175: 242-6, 2006.
  • Shefi S, Turek PJ: Definition and current evaluation of subfertile men. Int Braz J Urol (In Press).

Joyce Tung, Ph.D.
Postdoctoral Fellow

I was a graduate student in the Program in Biological Sciences, and worked with Renee from 2000 to 2005. My thesis focused on understanding the function of the Deleted in AZoospermia-Like (DAZL) gene in mammalian germ cell development. To this end, we screened infertile male and female patient populations for sequence variants in the human DAZL gene, and found several polymorphisms that were significantly associated with parameters such as age at ovarian failure and sperm count, showing that DAZL is indeed required for human fertility. We also studied the embryonic phenotype of the mouse Dazl knockout using a germ cell-specific Oct4-GFP reporter, and showed that in the mutant, germ cells are lost in both sexes before e14.5, which is earlier than previously reported. By real time PCR in sorted germ cells, we showed that this loss may be due to misregulation of important germ cell genes, many of which were expressed at aberrantly high or low levels. Finally, we performed an evolutionary analysis of the DAZ gene family, of which DAZL is a member, in primate lineages.

After my postdoc with Dr. Gregory Barsh at Stanford University, I moved to 23andMe, a company that does DNA testing and interpretation, where I am now a senior human geneticist. 

  • Tung JY., Luetjens CM, Wistuba J, Xu EY, Reijo Pera RA, Gromoll J. Evolution of the DAZL and BOULE reproductive genes was not affected by introduction of DAZ. Development, Genes & Evolution (in press)
  • Tung JY, Rosen MP, Nelson LM, Turek PJ, Witte JS, Cramer DW, Reijo Pera RA. Variants in Deleted in AZoospermia-Like (DAZL) are correlated with reproductive parameters in men and women. Hum Genet. Past Lab Members

Leslie Woo
PhD Candidate, University of Chicago

I was a member in the lab during the summer of 1998. At the time, I had just finished my freshman year of college and wanted to get some research experience. I can't think of a better place to have landed than with Renee and her lab crew! My main project was to analyze blood DNA samples from infertile males for specific deletions on the Y chromosome, which were implicated in male infertility. Currently, I am in my fifth year of graduate school at the University of Chicago in the Department of Biochemistry and Molecular Biology. My project is focused on the family of human RecQ helicases. These proteins are important in cellular processes like replication, recombination, and repair. The RecQ helicases have been found to play a critical role in the maintenance of genomic stability. My latest work has been on the fourth family member, the RECQL4 helicase. Mutations in this gene have been linked to the development of Rothmund-Thomson syndrome (RTS), which is characterized by skeletal and skin abnormalities, symptoms of premature aging, and a predisposition to cancer. The broad goals of this research are to try and better understand the regular aging process and also learn what factors in aging predispose individuals to cancer.


Eugene Xu, Ph.D.
Assistant Professor, Northwestern University

Germ cells are unique in that they are the only cell type in our bodies that is both totipotent and immortal. How germ cells in early embryos are formed and further developed into sperm and eggs remain one of the central questions in biology and a better understanding of this question could impact directly on our strategy in developing the diagnostic methods and treatment of diseases such as cancer, infertility and many other reproductive syndromes affecting men and women's health. The overall goal of my research program is to understand the genetic and developmental mechanisms of mammalian germline development, in particular how key events such as maintenance/differentiation of germline stem cells and entry into meiosis are regulated in mammals. The pathways that develop germ cells appear to be conserved broadly, at least in outline, in organisms as diverse as insects and mammals. We proposed that there exists conserved core machinery that regulates the germ cell development and we wish to define the components of this underlying machinery through a combined evolutionary, genomic and genetic approach.

Through bioinformatics analysis, we are examining and comparing the known regulators for the germ cell development in both Drosophila and mice to identify conserved components. Using genomics and microarray tools, we performed whole-genome expression assay on Drosophila developing gonads and established the transcription profiles for fruitfly germ cell development. This transcription profiles are now being compared to the gene expression pattern of mouse germ cell development to identify novel conserved regulators with emphases on germline stem cell regulator and meiotic regulators. To examine the functions of those conserved regulators, we generate and characterize mouse knockout mutations disrupting the conserved stem cell and meiotic regulators in the lab. We are also exploring to use embryonic stem cell system as an in-vitro model for germ cell differentiation and to determine the roles of conserved regulators in germ cell differentiation through RNAi. It is our hope that our multi-prone approach will help us to unveil the underlying molecular machinery of germ cell development and to further our understanding on stem cell biology and reproductive biology.

  • Xu, E. Y., D. Lee, A. Klebes, P. J. Turek, T. Kornberg and R. Reijo Pera (2003) Human BOULE rescues the meiotic defects in infertile flies Human Molecular Genetics. Vol 12(2):169-175.
  • Wu, C.-I. and E. Y. Xu (2003) Sexual antagonism and X inactivation- the SAXI hypothesis. Trends in Genetics 19(5): 243-7
  • Xu, E. Y., F. Moore, R. Reijo Pera (2001) A gene family required for human germ cell development evolved from an ancient meiotic gene conserved in metazoans. PNAS Vol 98:7414-7419
  • C. Marc Luetjens, E. Y. Xu, Renee A. Reijo Pera, Axel Kamischke, Eberhard Nieschlag, Jörg Gromoll (2004) Association of meiotic arrest in infertile men and lack of BOULE protein expression. J. Clinical Endocrinology and Metabolism 89(4):1926-33


Past RRP LabMembers
Vanessa Angeles
Katherine Bianco, M.D.
James Byrne, Ph.D.
Michael Castillo, M.D.
Amander Clark, Ph.D.
Ucheh Ezeh, M.D.
Marty Flores
Mark Fox, Ph.D.
Kelly Haston, M.S.
Kehkooi Kee, Ph.D.
Nina Kossack
Juanito Meneses, B.A.
Frederick Moore, Ph.D.
Ha Nam Nguyen
Cory Nicholas
Sarita Panula, M.S.
Nick Salmon, Ph.D.
Shai Shefi, M.D.
Henrike Siemen, M.S.
Joyce Tung, Ph.D.
Connie Wong, Ph.D.
Leslie Woo
Eugene Xu, Ph.D.


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