The Scientist Who Revealed Nature's Hidden Control Switches
Imagine if every cell in your body had the same blueprint, yet your liver knew to filter toxins while your heart knew to pump blood. This cellular intelligence exists throughout nature, and Lars Hennig (1970-2018), a pioneering geneticist, dedicated his career to understanding how plants achieve similar marvels.
Though his life was cut short at 47, Hennig's work fundamentally changed how we understand the hidden switches that control plant development—research with crucial implications for agriculture, climate change adaptation, and basic science.
Hennig's scientific journey began in Germany and took him to prestigious institutions across Europe, eventually landing him as a Professor of Genetics at the Swedish University of Agricultural Sciences in Uppsala1 . Unlike classic genetics that studies the DNA sequence itself, Hennig specialized in epigenetics—the layer of instructions that tells genes when and where to turn on or off. His particular fascination centered on how plants manage complex developmental processes like flowering time, despite all their cells containing identical genetic material. This article explores how Hennig's elegant research uncovered the molecular mechanisms behind these phenomena, revealing nature's sophisticated control systems that operate beyond the genetic code.
PhD student
Albert Ludwigs University of Freiburg
Dynamic behavior and interactions of plant photoreceptors1
Independent research group leader
ETH Zurich
Chromatin-based regulation of flowering time1
Professor
Swedish University of Agricultural Sciences, Uppsala
Polycomb group proteins and chromatin modifications in plant development and stress responses1
PhD Students
Postdoctoral Fellows
Publications
Major Tools Developed
Lars Hennig was more than just a brilliant researcher—he was a dedicated mentor who guided 11 PhD students and 11 postdoctoral fellows to successful careers, fostering a collaborative lab environment where scientific curiosity thrived1 . Colleagues remember him as a scientist with "unwavering scientific curiosity" and "astounding breadth of knowledge" across multiple research fields, coupled with an uncanny ability to recall virtually every relevant published study1 .
His research output was both prolific and profound, documented in over 100 scientific publications that continue to influence the field of plant epigenetics1 . Beyond his specific discoveries, Hennig helped develop pioneering tools for the scientific community, including Genevestigator, a powerful search engine for mining gene expression data, and establishment of MIAME annotation standards for plant genome-wide profiling1 . This combination of technical innovation and biological insight made him a unique force in plant science.
To appreciate Hennig's contributions, we first need to understand some key concepts. Rather than being a simple string of information, DNA is carefully packaged within a complex called chromatin—think of yarn wrapped around spools. These "spools" are made of proteins called histones, and how tightly or loosely the DNA is wrapped determines whether genes can be accessed and activated.
This packaging system constitutes a secondary code beyond DNA—an epigenetic layer that responds to environmental cues and developmental signals. Hennig focused particularly on:
Chemical tags (like methyl or acetyl groups) added to histones that can either open up or condense chromatin structure
Critical protein complexes that maintain repressed gene states by adding specific histone modifications
The dynamic reorganization of chromatin structure during development
These mechanisms explain how identical genetic information can produce different cell types and how environmental experiences can influence gene expression without altering the underlying DNA sequence.
DNA wraps around histone proteins to form nucleosomes, which fold into higher-order chromatin structures.
Hennig's work converged on a particularly fascinating protein called MULTICOPY SUPPRESSOR OF IRA 1 (MSI1), which he affectionately called the 'Swiss-army-knife' protein due to its remarkable versatility1 . His research revealed that MSI1 wasn't a specialist with a single job but rather a multi-talented player that served as a component of several distinct protein complexes:
This multi-functionality made MSI1 a central hub for understanding how different chromatin-modifying activities could be coordinated. Hennig's work demonstrated that these functions were genetically separable—the protein could be involved in different processes independently1 .
MSI1 participates in multiple protein complexes with distinct functions in chromatin regulation.
Much of Hennig's most influential work addressed a fundamental question: How do chromatin-modifying complexes coordinate to control developmental transitions? His research group employed sophisticated biochemical and genetic approaches in Arabidopsis (a model plant) to understand how MSI1 interacts with other key proteins.
The methodology followed this general流程:
Hennig's team made several landmark discoveries:
| Discovery | Method | Significance |
|---|---|---|
| MSI1 connects LHP1 to PRC2 | Immunoprecipitation + mass spectrometry1 | Revealed linkage between major chromatin complexes |
| MSI1 controls flowering time | Analysis of modified plants1 | Explained environmental influence on development |
| UBP12/13 associate with PRC2 | LHP1 immunoprecipitation1 | Identified new Polycomb network players |
| MSI1 regulates drought response | Stress assays in mutants1 | Showed epigenetic role in adaptation |
Perhaps the most significant finding was that MSI1 physically connects the protein LHP1 to the PRC2 complex1 . This was crucial because LHP1 recognizes the H3K27me3 histone mark (a repression signal placed by PRC2), creating a potential self-reinforcing loop that could maintain gene repression patterns as cells divide. This provided a mechanistic explanation for how epigenetic states could be stable through generations of cells.
| Reagent/Technique | Function in Research | Role in Hennig's Work |
|---|---|---|
| Chromatin Immunoprecipitation (ChIP) | Allows mapping of histone modifications and protein binding across genome | Identified genome-wide patterns of histone variant distribution1 |
| Arabidopsis thaliana | Model plant with well-characterized genetics and small genome | Primary organism for studying flowering time and development1 |
| Mass spectrometry | Identifies and characterizes proteins in complex mixtures | Analyzed protein complexes immunoprecipitated with MSI1 and LHP11 |
| Genevestigator | Bioinformatics tool for mining gene expression data | Enabled comparative analysis of gene expression patterns1 |
| AGRONOMICS1 microarray | Specialized chip for measuring gene expression in plants | Expanded options for transcriptomics and ChIP-chip experiments1 |
Hennig's impact extended far beyond his specific discoveries about chromatin. He recognized that progress in science depends on shared resources and collaborative spirit. With colleagues, he helped develop powerful bioinformatics tools that became indispensable to plant researchers worldwide1 :
A sophisticated search engine for mining and comparing gene expression data1
BioinformaticsA technological platform that expanded options for genome-wide profiling studies1
GenomicsAnnotation standards that helped ensure reproducibility and data sharing in plant genomics1
Data StandardsHe also co-initiated the successful biannual European Workshop Series in Plant Chromatin, creating a regular forum for specialists to exchange ideas and foster collaborations1 . As an associate editor and Flowering Newsletter editor for the Journal of Experimental Botany from 2012 to 2017, he helped shape the field and established the Flowering Highlights blog to disseminate cutting-edge research1 .
Hennig's contributions spanned research, tool development, and community building in plant epigenetics.
Lars Hennig's unexpected passing in 2018 left a void in plant science, but his legacy continues through multiple channels:
Principles of chromatin-based control of plant development
Resources enabling discoveries worldwide
Students and postdocs advancing science
Collaborative networks and meetings
Hennig's research has particular relevance as we face climate change challenges, since the epigenetic mechanisms he studied help plants respond to environmental stresses like drought1 . His work on flowering time control has implications for agriculture and crop yields.
Outside the lab, Hennig was remembered for making science "lively and enjoyable" with laboratory lunches sweetened with Swiss chocolates, celebrations of accepted manuscripts, and outdoor activities ranging from mountain hikes to kayaking on the Baltic Sea1 . He combined rigorous science with human warmth, insisting on multiple experimental controls and critical judgment of data while simultaneously caring about the personal and professional growth of his team members1 .
Though Hennig expressed doubt about "absolute truth" in biology and believed that "life is not designed to be fair," his passionate quest for both fairness and truth left an indelible mark on science and on those who worked with him1 . His work continues to inspire new generations of researchers to explore the elegant complexity of epigenetic regulation—the hidden control system that helps plants, and all living organisms, achieve their full potential from a single blueprint.
Hennig's work has applications in agriculture, climate adaptation, and basic plant science.