Draft:Charlotte Helfrich-Förster Draft

Charlotte Helfrich-Förster
Born	Aug. 30, 1957 Heilbronn-Sontheim, Baden-Württemberg, Germany
Education	University of Stuttgart, Eberhard Karls University of Tübingen, Max Planck Institute for Biological Cybernetics, Tübingen
Title	Senior Professor of Neurobiology and Genetics
Children	2

Charlotte Helfrich-Förster (Born August 30, 1957 in Heilbronn-Sontheim) is a German zoologist, neurobiologist, and professor at the University of Würzburg. Förster is particularly known for her research into the mechanisms by which the internal clock functions in insects.

Life

Charlotte Helfrich-Förster was born as the first of two daughters to a teacher and a housewife. She studied biology at the University of Stuttgart from 1976 to 1977, then received her diploma from Eberhard-Karls University of Tübingen in 1981. She completed her diploma thesis at the Eberhard Karls University of Tübingen under the supervision of Professor Wolfgang Engelmann. She earned her doctorate in 1985 at the Botanical Institute of the University of Tübingen working under Dr. Wolfgang Engelmann. Differing from her previous work as a plant physiologist, her doctoral work focused on the circadian clock in the brains of flies and her doctoral thesis was on the topic of "Investigations on the circadian system of flies". Specifically, during her PhD, she identified the first candidates for circadian clock neurons, inspiring her to further explore this area of research . She was postdoctoral fellow at the Eberhard Karls University of Tübingen from 1986 to 1987 and at the Max-Planck-Institute of Biological Cybernetics, Tübingen from 1994 to 1995. In 2000, she completed her habilitation in zoology, and in 2001, she became a professor of zoology at the University of Regensburg. Since 2009, she has held the chair for neurobiology and genetics at the University of Würzburg. In 2012, she established the DFG (German Research Foundation) Collaborative Research Centre Insect timing: mechanisms, plasticity and interactions.

Scientific contribution

Förster's main interest is to understand the function of internal clocks at the molecular and neuronal level. She is also interested in clarifying how internal clocks synchronize to cyclical changes in the environment, and how they control behavior. Since the function of internal clocks is highly conserved in the animal kingdom, the fruit fly, Drosophila melanogaster, is best suited to investigate these questions due to their genetic accessibility. Förster elucidated the neural clock network in the fruit fly's brain in detail. Furthermore, Förster showed that special neuropeptidergic neurons in this clock network are important for the rhythmic activity of the fly. These are neurons that express the neuropeptide "pigment-dispersing factor" (PDF). PDF neurons are essential for maintaining rhythmic activity in the absence of external cues such as light and temperature cycles. In a normal 24-hour day, the PDF neurons are important for normal morning activity and determining the time of the animals' evening activity. However, other clock neurons are essential for evening activity, including those that express the neuropeptide “ion transport peptide” (ITP). Together with results from other research groups, Charlotte Helfrich-Förster's investigations led to a generally valid model of activity control through morning and evening oscillators.

Förster's second scientific focus is the elucidation of the synchronization of the internal clock by external timers, in particular by light-dark cycles. In her doctoral thesis, she showed that the activity rhythm of eyeless fruit flies can still be synchronized to light-dark cycles, which supports the existence of extraocular photoreceptors. Such photoreceptors have also been found in the form of an extraretinal eye and in the form of the blue light pigment cryptochrome. In numerous works, and in national and international collaboration with many scientists, Förster largely clarified the importance and role of fruit flies' photoreceptor organs and photopigments for the synchronization of the fruit fly. She also studied the role of a seventh rhodopsin, Rh7, where there is increasing evidence that this is also involved in the synchronization of the internal clock to light. Adding onto the work done by Förster's group, another research group found that Rh7 is a photosensor that contributes to non-visual photoreception. It is also unclear why the fly needs so many photoreceptors for its internal clock. This may be due to the fact that the spectral changes during twilight, which enable the most precise determination of time, have to be perceived. Very similar mechanisms have also been considered for mammals. Among the various photopigments, cryptochrome is particularly interesting because in addition to the perception of light, it also seems to act as a magnetic receptor.

In comparative studies, Förster and her research group are also investigating the neural network of the internal clock of other insects, particularly that of northern Drosophila species. These flies are particularly interesting because they experience completely different environmental conditions than southern species and differ from Drosophila melanogaster in both activity patterns and neural clock networks. This suggests that the internal clock has evolved to adapt to the environment.

Research projects

Förster also conducts her research with the help of third-party funding.

• As part of the EU-funded project “FP7-People-2012-ITN: INsecTIME”, which ran from 2012 to March 31, 2017, she is investigating the photoperiodic control of the Diapause in different organisms (Firebug, Olive fly, Drosophila melanogaster, Drosophila melanogaster, Drosophila ezoana and Chymomyza costata (fly larvae). Adapting to the coming winter in a timely manner is vital for all animals - if they start storing fat reserves and stopping reproduction too late, they and their offspring will hardly survive the winter. The falling temperatures in autumn are only partially suitable for anticipating winter, as cold days also occur in summer and autumn is quite warm in some years. A reliable indicator of the approaching winter is the decreasing day length (photoperiod). Insects typically begin overwintering when the photoperiod falls below a critical value and temperatures are low. It is commonly assumed that the circadian clock is responsible for measuring day length, but how this happens is largely unknown. Furthermore, it is unclear how day length information is passed on to the hormonal centers in the brain that ultimately trigger diapause.
• Of the DFG The Collaborative Research Center 1047 is funded from January 1, 2013 to December 31, 2016 Insect timing: mechanisms, plasticity and interactions. Förster is involved here with two of his own projects. The first subproject deals with the circadian clock networks of selected insects. An important prerequisite for understanding the daily “timing” of insects is the functional characterization of the neural clock network in the brain. Förster contributes to this understanding by elucidating not only the clock network of different Drosophila species with sequenced genomes and with different habitats, but also, in collaboration with other researchers, that of social insects such as bees and ants. Bees and ants have a strong time memory and are capable of solar compass orientation. To do this, they need an internal clock that is connected to the neural structures that are responsible for learning and memory as well as navigation in space. The second subproject is about the role of photoreceptors in the synchronization of the internal clock of Drosophila and other insects to natural conditions.

Publications

• Research Gate Profile

Honors and awards

• 2021: Admission as a member of the National Academy of Sciences Leopoldina
• 2014: Karl Ritter von Frisch Medal
• 2012: Joliot Chair at the Neurobiology Laboratory, ESPCI ParisTech
• 2011: Ariens-Kappers Medallion der „European Biological Rhythms Society“
• 2008: SRBR (Society of Biological Rhythm Research) Member at Large
• 2005: Aschoff-Honma Prize from the Japanese “Honma Foundation of Life Science” in recognition of an outstanding contribution to the scientific field of biological rhythms
• 2003: Awarded the Aschoff’s Ruler-Price
• 2000: Research grant from the German Research Foundation
• 1998: Margarete von Wrangell Habilitationsstipendium
• 1996: Research grant from the German Research Foundation
• 1986: Attempto Prize from the University of Tübingen for neurobiological research

Weblinks

• Website at the German Neuroscientific Society

References

1. Helfrich-Förster, Charlotte. “Career Perspective.” Npj Biological Timing and Sleep 2, no. 1 (April 2, 2025): 14. https://doi.org/10.1038/s44323-025-00028-2.
2. ^{a b c} University of Würzburg: Chair of Neurobiology and Genetics (Memento from October 8, 2016 in Internet Archive)
3. ↑ University of Würzburg: Scientific career (Memento from October 8, 2016 in Internet Archive; PDF; 185 kB)
4. ^{a b} Timing in insects: mechanisms, plasticity and fitness consequences. Julius Maximilians University of Würzburg (2013–2016)
5. ↑ Helfrich-Förster, C. (2004). The circadian clock in the brain: a structural and functional comparison between mammals and insects. Journal of Comparative Physiology. A, Neuroethology, Sensory, Neural, and Behavioral Physiology, 190(8), 601–613. doi:10.1007/s00359-004-0527-2
6. ↑ Helfrich-Förster, C. (2005). Neurobiology of the fruit fly’s circadian clock. Genes, Brain and Behavior, 4(2), 65–76. doi:10.1111/j.1601-183X.2004.00092.x
7. ↑ Helfrich-Förster, C., Shafer, O. T., Wülbeck, C., Grieshaber, E., Rieger, D., & Taghert, P. (2007). Development and morphology of the clock-gene-expressing lateral neurons of Drosophila melanogaster. The Journal of Comparative Neurology, 500(1), 47–70. doi:10.1002/cne.21146
8. ↑ Helfrich-Förster, C., Yoshii, T., Wülbeck, C., Grieshaber, E., Rieger, D., Bachleitner, W., … Rouyer, F. (2007). The lateral and dorsal neurons of Drosophila melanogaster: new insights about their morphology and function. Cold Spring Harbor Symposia on Quantitative Biology, 72, 517–525. doi:10.1101/sqb.2007.72.063
9. ↑ Hermann-Luibl, C., & Helfrich-Förster, C. (2015). Clock network in Drosophila. Current Opinion in Insect Science, 7, 65–70. doi:10.1016/j.cois.2014.11.003
10. ↑ Helfrich-Förster C, Homberg U (1993) Pigment-dispersing hormone-immunoreactive neurons in the nervous system of wild-type Drosophila melanogaster and of several mutants with altered circadian rhythmicity. J Comp Neurol 337, 177-190.
11. ↑ Helfrich-Förster, C. (1995). The period clock gene is expressed in central nervous system neurons which also produce a neuropeptide that reveals the projections of circadian pacemaker cells within the brain of Drosophila melanogaster. Proceedings of the National Academy of Sciences, 92(2), 612–616.
12. ↑ Helfrich-Förster, C. (1998). Robust circadian rhythmicity of Drosophila melanogaster requires the presence of lateral neurons: a brain-behavioral study of disconnected mutants. Journal of Comparative Physiology A, 182(4), 435–453. doi:10.1007/s003590050192
13. ↑ Helfrich-Förster, C., Täuber, M., Park, J. H., Mühlig-Versen, M., Schneuwly, S., & Hofbauer, A. (2000). Ectopic expression of the neuropeptide pigment-dispersing factor alters behavioral rhythms in Drosophila melanogaster. The Journal of Neuroscience: The Official Journal of the Society for Neuroscience, 20(9), 3339–3353.
14. ↑ Yoshii, T., Wülbeck, C., Sehadova, H., Veleri, S., Bichler, D., Stanewsky, R., & Helfrich-Förster, C. (2009). The neuropeptide pigment-dispersing factor adjusts period and phase of Drosophila’s clock. The Journal of Neuroscience: The Official Journal of the Society for Neuroscience, 29(8), 2597–2610. doi:10.1523/JNEUROSCI.5439-08.2009
15. ↑ Hermann-Luibl, C., Yoshii, T., Senthilan, P. R., Dircksen, H., & Helfrich-Förster, C. (2014). The ion transport peptide is a new functional clock neuropeptide in the fruit fly Drosophila melanogaster. The Journal of Neuroscience: The Official Journal of the Society for Neuroscience, 34(29), 9522–9536. doi:10.1523/JNEUROSCI.0111-14.2014
16. ↑ The activity rhythm of Drosophila melanogaster is controlled by a dual oscillator. (o. J.). Abgerufen am 4. April 2017, von https://www.researchgate.net/publication/223763985_The_activity_rhythm_of_Drosophila_melanogaster_is_controlled_by_a_dual_oscillator.
17. ↑ Rieger, D., Shafer, O. T., Tomioka, K., & Helfrich-Förster, C. (2006). Functional analysis of circadian pacemaker neurons in Drosophila melanogaster. The Journal of Neuroscience: The Official Journal of the Society for Neuroscience, 26(9), 2531–2543. doi:10.1523/JNEUROSCI.1234-05.2006
18. ↑ Helfrich-Förster, C. (2009). Does the Morning and Evening Oscillator Model Fit Better for Flies or Mice? Journal of Biological Rhythms, 24(4), 259–270. doi:10.1177/0748730409339614
19. ↑ Yoshii, T., Rieger, D., & Helfrich-Förster, C. (2012). Two clocks in the brain: an update of the morning and evening oscillator model in Drosophila. Progress in Brain Research, 199, 59–82. doi:10.1016/B978-0-444-59427-3.00027-7
20. ↑ Helfrich-Förster, C. (2014). From Neurogenetic Studies in the Fly Brain to a Concept in Circadian Biology. Journal of Neurogenetics, 28(3–4), 329–347. doi:10.3109/01677063.2014.905556
21. ↑ Helfrich, C., & Engelmann, W. (1983). Circadian rhythm of the locomotor activity in Drosophila melanogaster and its mutants ‘sine oculis’ and ‘small optic lobes’. Physiological Entomology, 8(3), 257–272. doi:10.1111/j.1365-3032.1983.tb00358.x
22. ↑ Emery, P., Stanewsky, R., Helfrich-Förster, C., Emery-Le, M., Hall, J. C., & Rosbash, M. (2000). Drosophila CRY is a deep brain circadian photoreceptor. Neuron, 26(2), 493–504.
23. ↑ Veleri, S., Rieger, D., Helfrich-Förster, C., & Stanewsky, R. (2007). Hofbauer-Buchner Eyelet Affects Circadian Photosensitivity and Coordinates TIM and PER Expression in Drosophila Clock Neurons. Journal of Biological Rhythms, 22(1), 29–42. doi:10.1177/0748730406295754
24. ↑ Rieger D., Stanewsky R., Helfrich-Förster C. (2003). Cryptochrome, compound eyes, Hofbauer-Buchner eyelets, and ocelli play different roles in the entrainment and masking pathway of the locomotor activity rhythm in the fruit fly Drosophila melanogaster. J Biol Rhythms 18, 377-391.
25. ↑ Yoshii T., Todo T., Wülbeck C., Stanewsky R., Helfrich-Förster C. (2008). Cryptochrome operates in the compound eyes and a subset of Drosophila’s clock neurons. J Comp Neurol 508, 952-966.
26. ↑ Yoshii T., Vanin S., Costa R., Helfrich-Förster C. (2009). Synergic entrainment of Drosophila’s circadian clock by light and temperature. J Biol Rhythms 24, 452-464.
27. ↑ Mazotta G., Rossi A., Leonardi E., Mason M., Bertolucci C., Caccin L., Spolaore B., Martin A.J.M., Schlichting M., Grebler R., Helfrich-Förster C., Mammi S., Costa R., Tosatto SCE. (2013). Fly cryptochrome and the visual system, Proc Natl Acad Sci USA 110(15), 6163-6168.
28. ↑ Schlichting M., Grebler R., Peschel N., Yoshii T., Helfrich-Förster C. (2014). Moonlight detection by Drosophila’s endogenous clock depends on multiple photopigments in the compound eyes. J Biol Rhythms 29, 75-86.
29. ↑ Yoshii T., Hermann-Luibl C., Kistenpfennig C., Tomioka K., Helfrich-Förster C. (2015). Cryptochrome dependent and independent circadian entrainment circuits in Drosophila. J Neurosci 35(15), 6131-6141.
30. ↑ Yoshii T., Hermann-Luibl C., Helfrich-Förster C. (2016). Circadian light-input pathways in Drosophila. Communicative & Integrative Biol 9(1), e1102805. doi:10.1080/19420889.2015.1102805.
31. ↑ Senthilan, P. R., & Helfrich-Förster, C. (2016). Rhodopsin 7–The unusual Rhodopsin in Drosophila. PeerJ, 4, e2427. doi:10.7717/peerj.2427
32. Sakai, Kazumi, Kei Tsutsui, Takahiro Yamashita, Naoyuki Iwabe, Keisuke Takahashi, Akimori Wada, and Yoshinori Shichida. “Drosophila Melanogaster Rhodopsin Rh7 Is a UV-to-Visible Light Sensor with an Extraordinarily Broad Absorption Spectrum.” Scientific Reports 7, no. 1 (August 4, 2017): 7349. https://doi.org/10.1038/s41598-017-07461-9.
33. ↑ Foster, R. G., & Helfrich-Förster, C. (2001). The regulation of circadian clocks by light in fruitflies and mice. Philosophical Transactions of the Royal Society of London. Series B, 356(1415), 1779–1789. doi:10.1098/rstb.2001.0962
34. ↑ Yoshii, T., Ahmad, M., & Helfrich-Förster, C. (2009). Cryptochrome Mediates Light-Dependent Magnetosensitivity of Drosophila’s Circadian Clock. PLOS Biology, 7(4), e1000086. doi:10.1371/journal.pbio.1000086
35. ↑ Kauranen H., Menegazzi P., Costa R., Helfrich-Förster C., Kankainen A., Hoikkala A (2012). Flies in the North: Locomotor behavior and clock Neuron organization of Drosophila montana. J Biol Rhythms 27, 377-387.
36. ↑ Hermann C., Saccon R., Senthilan P., Domnik L., Dircksen H., Yoshii T., Helfrich-Förster C. (2013). The circadian clock network in the brain of different Drosophila species. J Comp Neurol 521(2), 367-388.
37. ↑ Menegazzi P., Dalla Benetta E., Beauchamp M., Schlichting M., Steffan-Dewenter I., Helfrich-Förster C. (2017). Adaptation of circadian neuronal network to photoperiod in high-latitude European Drosophilids. Curr Biol 27, 1-7.
38. ^{a b} University of Würzburg: Projects of the AG Förster (Memento from October 8, 2016 in Internet Archive)
39. ↑ K. M. Vaze, C. Helfrich-Förster: Drosophila ezoana uses an hour-glass or highly damped circadian clock for measuring night length and inducing diapause. In: Physiological Entomology. 41, 4, 2016, S. 378–389.
40. ↑ University of Würzburg: The circadian clock network of selected insects (Memento from October 8, 2016 in Internet Archive)
41. ↑ University of Würzburg: The role of photoreceptors in the synchronization of Drosophila's clock to natural conditions (Memento from October 8, 2016 in Internet Archive)
42. ↑ Member entry from Charlotte Förster at the German Academy of Natural Scientists Leopoldina
43. ↑ DZG: The Karl Ritter von Frisch Medal 2014 goes to the neurobiologist Charlotte Helfrich-Förster (Memento from September 15, 2016 in Internet Archive)