Talk by Hong Gil Nam – University of Copenhagen

Talk by Hong Gil Nam

On 2 July 2015 at 15.30-16.30 Professor Hong Gil Nam from Daegu Gyeongbuk Institute of Science and Technology (DGIST) in Korea will give a talk about:

Systems Biology of Plant Senescence and Death: How do plants know when to die and how to die?

Aging, a process of age-dependent functional switching of cells, organs, and organisms, is a life history strategy, eventually leading to senescence and death. Our main question is how living organisms know when and how to die.

In plants, we previously identified a death circuit with the trifurcate feed-forward pathway involving EIN2, ORE1, and miR164 (Science, 2009), which explains inevitable death. ORE1 is one of 109 NAC transcription factors (TF) of which combinatorial dimerization are likely to regulate age-associated TF networks including NACs. We are studying how the NAC transcriptional factor networks are shifting along the life span and how the network transition controls aging process. To extend the age associated molecular network, we are employing systems-level analyses including next generation sequencing and bioinformatic approaches in Arabidopsis. Through this study, we aim to understand the structure and dynamics of molecular networks during the lifespan, and to provide a plausible clue to reprogram aging process.

Senescence program is one of well-known biological processes to increase plant fitness in given environments. Studies in programs for aging and senescence control in various natural accessions of Arabidopsis can reveal how senescence program are evolved and diversified. Plant phenotype high-throughput investigators that we are developing, together with GWA approach will provide evolutionary and adaptive interaction among environment, phenome, and genome.

We are also studying interaction of the two different time measuring systems, aging and circadian clock. We found that leaf aging affects entrainment of circadian rhythm in Arabidopsis and this association may modulate with age-dependent leaf developmental processes.

Senescence and death is in part systemically controlled at the organismal level. We are employing rice as a model system to understand the mechanism underlying the systemic senescence, especially during grain filling period. Different and coordinated senescence programs were elucidated between upper two leaves and this type of systemic regulation may contribute to increase grain yield by properly supplying two major nutrients, carbon and nitrogen.

We are extending our aging research into animal aging. As a first step, we are exploring the role of regulatory RNAs in animal aging process. We performed entire lifespan mRNA and small RNA seq of various mouse organs including hippocampus and hypothalamus. Our study highlighted the importance of miRNA-mediated regulatory networks in controlling the hippocampal memory function.

What is the relationship between organ aging and organismal aging? We used islets to answer this question and showed that cells in islets show little aging in their function but a major cause of the age-dependent loss of islet function is due to aging of the blood vessels in islets, which can be rejuvenated in a young host and implies that a target of type II diabetes may expanded toward the vessel aging in islets.

C. elegans has been a favorite model for genetic study of aging. We are exploring novel RNA-regulatory mechanisms involved in the aging process of C. elegans. Decline of physical strength is an important aging-associated lesion. Using C. elegans as a model system, we are exploring the causative regulatory pathways for the age-associated physical decline.  

In this talk, I will deliver our research efforts and insights toward aging and death.

Professor Hong Gil Nam received his bachelor’s degree in chemistry from Seoul National University, and doctor’s degree in biochemistry from University of North Carolina.

Dr. Nam was designated as the National Scholars of Korea in 2010 for his achievement in establishing the theory that plant senescence is controlled by genetic programs.

Currently Dr. Nam is one of DGIST Fellows, and holds the position of Director of the Center for Plant Aging Research, Institute for Basic Science.

Prof. Hon Gil Nam was invited by Thomas Georg Roitsch and Section for Crop Sciences at Department of Plant and Environmental Sciences, University of Copenhagen.