Professor; Associate Chair for Research and Facilities
3140 East Science Hall, Science & Engineering Complex
(205) 975-4049
Research and Teaching Interests: Epigenetics and chromatin
Office Hours: By appointment
Education:
- B.S., University of Missouri Columbia, Biology (with Honors)
- Ph.D., Washington University in St. Louis, Evolutionary and Population Biology
Dr. Riddle obtained her undergraduate degree from the University of Missouri in Columbia, carrying out research in a maize lab. During her graduate work at Washington University in St. Louis, she first learned about epigenetics, a research field that focuses on heritable changes in phenotypes that are not associated with changes in the DNA. At the time, epigenetics was poorly understood, and her fascination with this field has grown with the scientific community’s increasing appreciation for the influence of epigenetics on other aspects of biology.
In her scientific career, Dr. Riddle has studied various aspects of epigenetics in plants and animals. Her lab at UAB utilizes a classical genetics model system, the fruit fly Drosophila melanogaster, to study various open questions in the area of epigenetics and chromatin.
-
Research Interests
My research focuses on understanding the mechanisms establishing and regulating epigenetic information, and how epigenetic systems ultimately contribute to gene regulation, disease, and other phenotypes. In addition to the genetic information encoded within the DNA, other forms of information exist in the cell. Epigenetic information is heritable, affects gene expression states and phenotypes, but is independent of DNA sequence. Examples of epigenetic systems include DNA methylation, histone modifications, and chromatin structure. These epigenetic systems play vital roles in gene regulation, and defects in epigenetic regulation have been implicated in a variety of human diseases including cancer. My lab uses the fruit fly Drosophila melanogaster as a model system to investigate epigenetic systems and their influence on development and gene regulation. Currently, there are three on-going projects in the lab:
- The HP1 protein family: Heterochromatin protein 1a (HP1a) was discovered as the first heterochromatin-associated protein. Its binding characterizes the heterochromatic regions of the fly genome, and homologs have been identified in species ranging from yeast to humans. The HP1a protein contains two conserved domains, the chromo domain, and the chromo-shadow domain. Based on this domain structure, four additional HP1 family proteins have been identified in Drosophila melanogaster. Of these, HP1B and HP1C, like HP1a, are ubiquitously expressed, while HP1D/RHINO and HP1E are restricted to the germline in females and males respectively. While HP1a binds large domains in heterochromatin, it also shows binding to active transcription start sites, where it is generally found in the company of HP1B and/or HP1C. We are using molecular genetics and genomics approaches to understand the relationship between HP1a, HP1B, and HP1C, and their effect on gene regulation.
- The role of epigenetics in exercise response: Exercise is a common form of treatment recommended to combat the increasing obesity problem observed in many countries. How individuals respond to exercise is highly variable, and the source of this variation is not well understood. We are using the fruit fly Drosophila melanogaster as a model for exercise biology. Taking advantage of the genetics resources available in Drosophila, our experiments are designed to determine the relative importance of genetics and epigenetics in generating the variability in exercise response.
- Epigenetic contributions to sex differences in aging: Typically, with age, both genome and epigenome stability decreases. DNA repair pathways function less well, chromatin modifiers become misregulated, and noise in gene expression increases. Currently, it is not clear if these same processes contribute to the sex differences in aging seen in many species. Together with our colleges in IISAGE, we investigate this question using Drosophila as a model. We are manipulating genome content, heterochromatin amount, DNA repair pathways, and more to define their role in sex-specific aging.
-
Recent Courses
- Biology of Sex
- Seminar in Genetics
- Investigative Techniques
- CLOne – Chromatin Laboratory 1
- Genetics
- Epigenetics
- Epigenetics Discussion/Journal Club
-
Graduate Students
Trainees
- Denise Horner
- Abigail Fox
- Gizem Turkmen
Alumni
- Jalen Bynum
- Heidi M. G. Johnson
- Sarah Sims
- James C. Walts
- Tristan Young
- Bre’ Minniefield, postdoctoral fellow
- Amit Paul, postdoctoral fellow
- John M. Schoelz, PhD
- Louis Watanabe, PhD
- Justina X. Feng, MS
- Jordan Favors, MS
- Samuel Gregory, MS
- Mina Momeni, MS
- Benjamin B. Mills, MS
- Christine McBride, MS
-
Select Publications
For a full list of publications, please visit Dr. Riddle's PubMed entry.
- Walts JC, Dave AA, and Riddle NC. The impact of exercise on protein levels in Drosophila melanogaster. (2026) Biol Open 15(1):bio.062342.
- Shi M, Li G, Araujo HM, Lee AS, Zhang J, Lee YL, IISAGE consortium, Cheong SH and Duan JE. Sex-biased transcriptome in in vitro produced bovine early embryos. Cell Biosci 15, 123 (2025).
- Walts JC and Riddle NC. Phosphorylation as a regulatory mechanism of HP1 protein multifunctionality. (2025) Chromosoma 134, 9.
- Byars ASX and Riddle NC. Unpredictable disturbance and its effects on activity behavior and lifespan in Drosophila melanogaster. (2025) Biol Open 14 (7): bio062071.
- Rayner JG, Bock SL, Lonski AJ, Riddle NC, and Wilkinson GS. Sex differences in DNA methylation in bats. (2025) Ann NY Acad Sci 1551, 115–128.
- Biga PR, Duan JE, Young TE, Marks JR, Bronikowski AM, Decena LP, Randolph EC, Pavuluri AG, Li G, Fang Y, Wilkinson GS, Singh G, Nigrin NT, Larschan EN, Lonski AJ, Riddle NC and IISAGE Consortium. Hallmarks of Aging: A User’s Guide for Comparative Biologists. (2025) Ageing Research Reviews 104: 102616.
- Johnson HM and Riddle NC. Early life exercise impacts physiology and lifespan in a sex- and genotype-dependent manner in a Drosophila melanogaster exercise model. (2024) Exp Geront 198:112630.
- Riddle NC, Biga PR, Bronikowski AM, Walters JR, Wilkinson GS, IISAGE Consortium. Comparative analysis of animal lifespan. Geroscience 46(1):171-181, doi:10.1007/s11357-023-00984-2. GeroScience Publication Award Honorable Mention.
- Adler FR, Anderson ARA, Bhushan A, Bogdan P, Bravo-Cordero JJ, Brock A, Chen Y, Cukierman E, DelGiorno KE, Denis GV, Ferrall-Fairbanks MC, Gartner ZJ, Germain RN, Gordon DM, Hunter G, Jolly MK, Karacosta LG, Mythreye K, Katira P, Kulkarni RP, Kutys ML, Lander AD, Laughney AM, Levine H, Lou E, Lowenstein PR, Masters KS, Pe'er D, Peyton SR, Platt MO, Purvis JE, Quon G, Richer JK, Riddle NC, Rodriguez A, Snyder JC, Szeto GL, Tomlin CJ, Yanai I, Zervantonakis IK, and Dueck HR. Modeling collective cell behavior in cancer: perspectives from an interdisciplinary conversation. Cell Syst 14(4):252-257, doi:10.1016/j.cels.2023.03.002.
-
Academic Distinctions and Professional Societies
- Named New Investigator for the UAB Nutrition Obesity Research Center (NORC), 2015
- Provost's Award for Faculty Excellence in Academic Engagement and Global Citizenship, 2014
- American Association for the Advancement of Science
- The Genetics Society of America
- UAB Sigma Xi – President-Elect (2017-2018); President (2018-2019)
- 2016 The John R Durant Award for Excellence in Cancer Research, 1st Place, Junior Faculty Category at the UAB Comprehensive Cancer Center 18th Annual Research Retreat and Research Competition
- 2013 The John R Durant Award for Excellence in Cancer Research, 2nd Place, Junior Faculty Category at the UAB Comprehensive Cancer Center 16th Annual Research Retreat and Research Competition
-
Student Groups
- UAB Genetics Club