Chromosome proliferation mechanisms in fruit fly and implications for understanding cancer

Dr. Don Fox

Don Fox, Ph.D.

Dr. Don Fox, Assistant Professor of Pharmacology and Cancer Biology at Duke, studies the processes of tissue repair and remodeling, both of which involve mitosis, in the fruit fly Drosophila melanogaster.  Mitosis is the process of cell division that normally results in two identical pairs of chromosomes being separated into each new cell.

Recently, Dr. Fox and his student Ben Stormo discovered that mitosis is very different when more than two identical pairs of chromosomes are present.  By carefully observing cells with these extra chromosomes as they enter mitosis, Stormo and Fox discovered a new type of chromosome separation that happens just before a cell undergoes the standard form of mitosis.  This newly discovered chromosome separation helps cells to cope with the challenge of separating all those extra chromosome copies. As many tumor cells have extra chromosomes, and as extra chromosomes can be generated by some forms of chemotherapy, these findings may have an important implication in the understanding of the mechanisms governing cancerous tumor progression. “Understanding these regulatory mechanisms brings us one step closer to understanding how some cancerous cells with extra chromosomes may proliferate in humans,” says Dr. Fox.

The paper was published in the Journal eLife on May 9, 2016.

A fruit fly cell with extra chromosomes at different stages of a disassembly process during mitosis. Image credit: Don Fox.

A fruit fly cell with extra chromosomes at different stages of a disassembly process during mitosis. Image credit: Don Fox.

Postdoctoral fellowships available: call for applications

Update: Please check out the FAQ page! (Updated July 5, 2016).

The Regeneration Next Initiative (RNI) was established by the Duke University School of Medicine to enhance discovery and applications in the broad field of tissue regeneration. Regeneration Next invites applicants for postdoctoral fellowships. This first round of fellowships is designed for postdoctoral associates who are currently performing research related to tissue regeneration in Duke University laboratories, and will provide two-year total funds of $55,000 to partially cover stipend, benefits, and research expenses.

RNI intends to support several new RNI Fellows each year. Trainees will receive support for two years and participate in mentored laboratory research, the annual Community Retreat, seminar series, and career development activities. It is important that Fellows are actively engaged in RNI activities.

RNI Fellows need not be US citizens or permanent residents.

Application materials
A. Cover Page – include name of applicant and title of proposal
B. Brief research proposal, consisting of Specific Aims (limited to 1 page), Importance of the Problem (limited to 1 page), and Research Design (limited to 3 pages). Limits will be strictly enforced.
C. Biosketch of the applicant, including their educational background, research experience, and publications.
D. 5 page standard NIH Biosketch of proposed mentor.
E. One-paragraph statement of applicant’s career plans.
F. Three letters of recommendation to be emailed directly to the Committee at regeneration@duke.edu. One of the three letters should be from the proposed mentor.

The deadline for the receipt of applications for this callout is July 15, 2016. Funding will begin September 1, 2016. Please send applications by email (as a single PDF file) to regeneration@duke.edu. In the Subject, please write RNI Fellows application – your name.

Questions about the callout may be directed to Dr. Sharlini Sankaran.

 

Junsu Kang, Ph.D. and Tissue Regeneration Enhancer Elements

Junsu Kang, Ph.D.

Junsu Kang, Ph.D.

Junsu Kang, Ph.D., a postdoctoral fellow in Ken Poss’s laboratory, studies how tissue regeneration programs are regulated. This April, Junsu led a study describing the discovery of tissue regeneration enhancer elements. These elements are DNA sequences that help turn genes on after injury that carry out key functions in highly regenerative tissues, such as the hearts and fins of zebrafish.

Junsu and colleagues also showed these elements can be engineered into simple DNA constructs that can boost the regenerative capacity of tissues, and that they can even be employed to control the expression of genes in the injured tissues of mammals like mice. The study was published in the April 14, 2016 issue of Nature.

Green signal visualizes activation of gene expression in an injured zebrafish heart (top) or fin (bottom) by a tissue regeneration enhancer element.

Green signal visualizes activation of gene expression in an injured zebrafish heart (top) or fin (bottom) by a tissue regeneration enhancer element.

The Silver Lab

Section of embryonic mouse brain [image 1] showing neural stem cell populations in red and new neurons in green. The Silver lab studies neural stem cells of the developing brain. We aim to understand how stem cells are able to produce both new neurons and new stem cells. Dysfunction of neural stem cells divisions can result in neurodevelopmental disorders such as microcephaly or autism. Therefore our studies can help elucidate fundamental aspects of stem cell biology as well as have clinical relevance.

brain-image

Image 1

Developing mouse brain [image 2] depicting activity of an enhancer (blue) active in early brain development. This was part of a study to identify enhancers relevant for human brain traits.

Enhancer expression in developing cortex

Image 2

Image of a mouse brain [image 3] showing dying cells within a developing brain. Green cells are neurons. Cells die as a result of mitotic defects in neural stem cells.

DOSC66_STLC_14h_Slc3_Sld6_EdU_Tuj1_Hoechst_CC3_40x-1

Image 3