Judy Leatherman

Postdoctoral Researcher, University of Pennsylvania, Perelman School of Medicine, Department of Cell and Developmental Biology

Area of Study: Stem Cell Biology

PhD, University of Pennsylvania, Perelman School of Medicine, Department of Genetics

Area of Study: Cell and Molecular Biology

BS, Eastern Mennonite University

Area of Study: Biology and Chemistry

Professor, University of Northern Colorado
School of Biological Sciences (2024 – Present)

Adult Stem Cell Biology

My research focuses on stem cell populations that live in the bodies of adult organisms and function to maintain tissue homeostasis. We study adult stem cells in the specialized microenvironments where they reside in the body, called the “stem cell niche”. We are interested in how stem cells are maintained in an undifferentiated state over the lifetime of the organism, and how the niche influences the choice between staying as a stem cell (“self-renewing”) or undergoing differentiation.

As a model system, my lab utilizes the well-defined stem cell niche in the testis of the genetically tractable model organism Drosophila melanogaster, a leading model system in adult stem cell biology. Here, stem cell activity leads to continual sperm production by male flies. We use classical and modern approaches for in vivo genetic manipulation to explore the molecular basis of niche functioning. Our basic research is performed with the expectation that findings in a simple model organism will reveal conserved aspects of stem cell biology relevant to the stem cells that live in our own bodies.

Our most recent work has focused on a family of genes called the ABC Transporters, which encode transmembrane proteins that pump toxins and other substrates into and out of cells. We have discovered several pumps that are required for stem cell maintenance, and we are working to determine why those proteins are important in the stem cell population.

Comparative Genomics

My lab is involved with the Genomics Education Partnership, a nationwide collaboration of faculty in bioinformatics. As part of this project, I work with independent study undergraduate students to carefully map the location and structure of genes of interest in poorly annotated species, and these results are then used in our collaborative work for comparative genomics investigations. Our projects have included diverse species within the Drosophila genus, Diorhabda tamarisk beetle species used in biological control projects in the US southwest, and the endangered Puerto Rican parrot Amazona vittata.

• Stanek, T. J., Leung, W., Shaffer, C., Leatherman, J., Anastas, A., Nguyen, E. K., Samuelson, K. B., Xu, P., Snell, A., Almaden, E., Arnhart, J., Krueger, K. G., Olaveja, I., Laughlin, A., Olaveja, I., Laughlin, A., Hester, J., Garrido, D., Oh, E., Volski, M., Panda, N., Mo, M., Cordes, E., Dalling, M., Kershaw, K., Arnott, M., Daly, S., Garcia, S., Thompson, P., Hastert, K., Sabb, D., Karpinski, K., Arora, M., Rius, N., LoBello, L., Jaramillo, S., Sonavane, O., Herrmann, A., Reid, L. K., Elgin, S. C.R., Arrigo, C., Ellison, C. E. (2025). Recombination suppression drives expansion of the Drosophila dot chromosome. Molecular Biology and Evolution, 42(12).. DOI: https://doi.org/10.1093/molbev/msaf304
• Backlund, A. E., Bain, B., Kite, K., Babbitt, C., Long, L. J., Leatherman, J., Schwartz, B., Rele, C. P., Reed, L. Gene model for the ortholog of rictor in Drosophila ananassae. microPublication biology, 2025, 10.17912/micropub.biology.000982. https://doi.org/10.17912/micropub.biology.000982
• Bicanovsky, G. N., Senkow, K. J., McColl, C., Mierisch, J., Agrimson, K. S., Long, L. J., Leatherman, J., Rele, C. P., Reed, L. K. (2025). Gene model for the ortholog of Sik3 in Drosophila mojavensis. microPublication biology, 2025, 10.17912/micropub.biology.001032. https://doi.org/10.17912/micropub.biology.001032
• Wipf, I., Anastas, A., Daulton, T., Nelson, L. L., Maity, S., Malone, K., Nguyen, E., Ramos, R., Wright, K., Xiong, J., Leatherman, J. (2024). Expression of ABC transporters in the Drosophila testis stem cell niche: Comparison of two approaches. Gene Expression Patterns, 54, 119386. DOI: https://doi.org/10.1016/j.gep.2024.119386
• Key, S. Catherine S., Van Stry, M., Lopatto, D., Siders, J., Leung, W., Sandlin, K. M., Rele, C. P., Leatherman, J., Faculty of the Genomics Education Partnership, Reed, L. K. (2023). Supporting the democratization of science during a pandemic: genomics Course-based Undergraduate Research Experiences (CUREs) as an effective remote learning strategy. Journal of Microbiology and Biology Education, 24(3). https://doi.org/10.1128/jmbe.00039-23
• Mues, N., Hammer, K., Leatherman, J. (2023). Pvr regulates cyst stem cell division in the Drosophila testis niche, and has functions distinct from Egfr. Cells & Development, 173, 203822. https://doi.org/10.1016/j.cdev.2022.203822
• Lopatto, D., Rosenwald, A. G., Burgess, R. C., Key, C. S., Van Stry, M., Wawersik, M., DiAngelo, J. R., Hark, A. T., Skeritt, M., Leatherman, J., Pullen, N. A., Buhler, J., Leung, W., Elgin, S. C.R., Reed (98 authors), L. K. (2022). Student Attitudes Contribute to the Effectiveness of a Genomics CURE. Journal of Microbiology & Biology Education, 23(2), e00208-21. https://doi.org/10.1128/jmbe.00208-21
• Johnson, B., Leatherman, J. (2021). Merlin and expanded integrate cell signaling that regulates cyst stem cell proliferation in the Drosophila testis niche. Developmental Biology, 477, 133-144. https://doi.org/10.1016/j.ydbio.2021.05.012
• Lopatto, D., Rosenwald, A. G., DiAngelo, J. R., Hark, A. T., Skerrit, M., Wawersik, M., Leatherman, J., Faculty of the Genomics Education Partnership (110 authors), Elgin, S. C.R. (2020). Facilitating Growth through Frustration: Using Genomics Research in a Course-Based Undergraduate Research Experience. Journal of Microbiology & Biology Education, 21(1), 21.1.6. https://doi.org/10.1128/jmbe.v21i1.2005
• Leatherman, J., Cleveland, L. (2019). Student exam performance in flipped classroom sections is similar to that in active learning sections, and satisfaction with the flipped classroom hinges on attitudes toward learning from videos. Journal of Biological Education. https://doi.org/10.1080/00219266.2019.1575266
• Leung, W., Shaffer, C. D., Leatherman, J., Modahl, C. M., Faculty and Students of the GEP (275 authors), Elgin, S. (2017). Retrotransposons Are the Major Contributors to the Expansion of the Drosophila ananassae Muller F Element. G3: Genes, Genomes, Genetics, 7(8), 2439-2460. https://doi.org/10.1534/g3.117.040907
• Elgin, S. C., Hauser, C., Holzen, T. M., Jones, C., Kleinschmit, A., Leatherman, J., The Genomics Education Partnership (2017). The GEP: Crowd-Sourcing Big Data Analysis with Undergraduates. Trends in Genetics, 33(2), 81-85. https://doi.org/10.1016/j.tig.2016.11.004
• Schaffer, C., Alvarez, C. J., Bednarski, A. E., Dunbar, D., Goodman, A. L., Reinke, C., Rosenwald, A. G., Wolyniak, M. J., Leatherman, J., (84 authors), Mardis, E. R., Buhler, J., Leung, W., Lopatto, D., Elgin, S. C. (2014). A Course-Based Research Experience: How Benefits Change with Increased Investment in Instructional Time. CBE—Life Sciences Education, 13(1), 111-130. https://doi.org/10.1187/cbe-13-08-0152
• Frietze, S., Leatherman, J. (2014). Examining the process of de novo gene birth: an educational primer on “integration of new genes into cellular networks, and their structural maturation”. Genetics, 196(3), 593-9. https://doi.org/10.1534/genetics.113.160895
• Leatherman, J. (2013). Stem cells supporting other stem cells. Frontiers in Genetics, 4, 257. https://doi.org/10.3389/fgene.2013.00257
• Leatherman, J., Dinardo, S. (2010). Germline self-renewal requires cyst stem cells and stat regulates niche adhesion in Drosophila testes. Nature Cell Biology, 12(8), 806-11. https://doi.org/10.1038/ncb2086
• Leatherman, J., Dinardo, S. (2008). Zfh-1 controls somatic stem cell self-renewal in the Drosophila testis and nonautonomously influences germline stem cell self-renewal. Cell Stem Cell, 3(1), 44-54. DOI: 10.1016/j.stem.2008.05.001
• Leatherman, J., Jongens, T. A. (2003). Transcriptional silencing and translational control: key features of early germline development. BioEssays : News and Reviews in Molecular, Cellular and Developmental Biology, 25(4), 326-35.
  https://doi.org/10.1002/bies.10247
• Leatherman, J., Levin, L., Boero, J., Jongens, T. A. (2002). Germ cell-less acts to repress transcription during the establishment of the Drosophila germ cell lineage. Current Biology, 12(19), 1681-5. DOI: 10.1016/S0960-9822(02)01182-X
• Kelly, C., Chin, A. J., Leatherman, J., Kozlowski, D. J., Weinberg, E. S. (2000). Maternally controlled (beta)-catenin-mediated signaling is required for organizer formation in the zebrafish. Development, 127(18), 3899-911. https://doi.org/10.1242/dev.127.18.3899
• Leatherman, J., Kaestner, K. H., Jongens, T. A. (2000). Identification of a mouse germ cell-less homologue with conserved activity in Drosophila. Mechanisms of Development, 92(2), 145-53. https://doi.org/10.1016/S0925-4773(99)00335-4
• Robertson, S. E., Dockendorff, T. C., Leatherman, J., Faulkner, D. L., Jongens, T. A. (1999). Germ cell-less is required only during the establishment of the germ cell lineage of Drosophila and has activities which are dependent and independent of its localization to the nuclear envelope. Developmental Biology, 215(2), 288-97. https://doi.org/10.1006/dbio.1999.9453
• Shimazu, A., Nah, H. D., Kirsch, T., Koyama, E., Leatherman, J., Golden, E. B., Kosher, R. A., Pacifici, M. (1996). Syndecan-3 and the control of chondrocyte proliferation during endochondral ossification. Experimental Cell Research, 229(1), 126-36. https://doi.org/10.1006/excr.1996.0350.
• Koyama, E., Leatherman, J., Noji, S., Pacifici, M. (1996). Early chick limb cartilaginous elements possess polarizing activity and express hedgehog-related morphogenetic factors. Developmental Dynamics, 207(3), 344-54. https://doi.org/10.1002/(SICI)1097-0177(199611)207:3<344::AID-AJA11>3.0.CO;2-4
• Koyama, E., Leatherman, J., Noji, S., Pacifici, M. (1996). Polarizing activity in early limb cartilaginous condensations. Annals of the New York Academy of Sciences, 785, 281-3. https://doi.org/10.1111/j.1749-6632.1996.tb56284.x
• Koyama, E., Yamaai, T., Iseki, S., Ohuchi, H., Nohno, T., Yoshioka, H., Hayashi, Y., Leatherman, J., Golden, E. B., Noji, S., Pacifici, M. (1996). Polarizing activity, Sonic hedgehog, and tooth development in embryonic and postnatal mouse. Developmental Dynamics, 206(1), 59-72. https://doi.org/10.1002/(SICI)1097-0177(199605)206:1<59::AID-AJA6>3.0.CO;2-%23
• Koyama, E., Leatherman, J., Shimazu, A., Nah, H. D., Pacifici, M. (1995). Syndecan-3, tenascin-C, and the development of cartilaginous skeletal elements and joints in chick limbs. Developmental Dynamics, 203(2), 152-62.
  https://doi.org/10.1002/aja.1002030204
• Pacifici, M., Iwamoto, M., Golden, E. B., Leatherman, J., Lee, Y. S., Chuong, C. M. (1993). Tenascin is associated with articular cartilage development. Developmental Dynamics, 198(2), 123-34.
  https://doi.org/10.1002/aja.1001980206