Nav: Home

Finding of STEMIN (STEM CELL INDUCING FACTOR) for feasible reprogramming in plants

July 11, 2019

Stem cells self-renew and give rise to cells that are differentiated during development. These differentiated cells can change into stem cells under appropriate conditions in most plants, in which this process is more readily apparent, and some animals. Researchers have previously succeeded in forming new shoots from intact leaves by inducing single transcription factors in Arabidopsis. However, it has not been clear whether these transcription factors induce meristematic tissue that subsequently induces stem cells or directly induces them. To this end, Assistant Professor Masaki Ishikawa and Professor Mitsuyasu Hasebe at the National Institute of Basic Biology in Japan, Designated Associate Professor Yoshikatsu Sato of the Institute of Transformative Bio-Molecules (WPI-ITbM) at Nagoya University in Japan and their collaborators found that induction of the transcription factor STEM CELL INDUCING FACTOR1 (STEMIN1) in leaves directly changes leaf cells into stem cells in the moss Physcomitrella patens. This discovery of a direct stem cell inducing factor will facilitate the further elucidation of the molecular mechanisms underlying stem cell formation in land plants.

In most plants and some animals, differentiated cells can revert to stem cells during or even after development under appropriate conditions. While stem cells do not appear to initiate after embryogenesis in mammalians, induction of some transcription factors induces conversion of somatic cells to induced pluripotent stem (iPS) cells. However, plant cells are more plastic than animal cells. In particular, stem cell formation is widely observed in the process of making new organs during development and regeneration in land plants. However, Professor Mitsuyasu Hasebe said, "Although some regulators involved in stem cell formation have been identified in angiosperms, understanding the molecular mechanisms of reprogramming and stem cell formation in land plants in general as well as their evolution is still challenging."

Prof. Hasebe and his colleagues aimed to understand molecular mechanisms underlying stem cell formation by using the moss Physcomitrella patens and started a research project named "ERATO Hasebe Reprogramming Evolution project" supported by the Japan Science and Technology Agency in 2005. This moss is a good model to study stem cell formation from differentiated cells. The leafy shoot (gametophore) is formed after a hypha-like branching growth of a filamentous tissue (protonema) has arisen from a spore. When a leaf is excised from a gametophore and cultivated on a culture medium, leaf cells facing the cut convert into stem cells that can undergo tip growth and cell division to produce protonema. In screening for factors involved in stem cell formation, Dr. Yohei Higuchi and Dr. Yoshikatsu Sato, a group leader of the project, succeeded in identifying a gene encoding a transcription factor that changes leaf cells into stem cells without wounding signals, thus leading to formation of protonemata. Dr. Sato said, "This gene was named STEMIN1 (STEM CELL-INDUCING FACTOR 1)".

After the project, Dr. Masaki Ishikawa succeeded in revealing the molecular mechanisms of STEMIN1 during stem cell formation. He said, "We found that STEMIN1 gene was activated in leaf cells that underwent stem cell formation in excised leaves. Furthermore, the deletion of STEMIN1 and its two homolog genes delayed the stem cell formation after leaf excision. These results indicate that STEMIN1 functions in an inherent mechanism to initiate formation of stem cells in Physcomitrella." To further understand this molecular mechanism, Ms. Mio Morishita, a graduate student from SOKENDAI (The Graduate University for Advanced Studies) focused on the STEMIN1-direct target genes. She found that the genes were marked by trimethylation of histone H3 at lysine-27 (H3K27me3), a so-called repressive histone modification, and were transcriptionally repressed in leaf cells. In contrast to this, she also said, "STEMIN1 induction in leaf cells specifically decreased the repressive histone modification levels in the STEMIN1-direct target genes before cell division and activated their gene expression, leading to the formation of stem cells."

Thus, this research group has demonstrated that STEMIN1 functions in an intrinsic mechanism underlying local histone modification changes to initiate stem cell formation. Prof. Hasebe said, "Our new findings will enhance studies on mechanistic insights regarding how a single transcription factor induces stem cell formation in land plants. In addition, since other land plants including angiosperms have orthologs of the STEMIN genes, further studies of this gene family should provide insight into whether this is a general mechanism for stem cell formation in land plants."
-end-
The above studies were published in Nature Plants on July 8th, 2019.

Reference:

Nature Plants

"Physcomitrella STEMIN transcription factor induces stem cell formation with epigenetic reprogramming" by *Masaki Ishikawa, *Mio Morishita, Yohei Higuchi, Shunsuke Ichikawa, Takaaki Ishikawa, Tomoaki Nishiyama, Yukiko Kabeya, Yuji Hiwatashi, Tetsuya Kurata, Minoru Kubo, Shuji Shigenobu, Yosuke Tamada, Yoshikatsu Sato, and Mitsuyasu Hasebe (*Co-first authors)

DOI: 10.1038/s41477-019-0464-2 (https://doi.org/10.1038/s41477-019-0464-2)

National Institutes of Natural Sciences

Related Stem Cells Articles:

More selective elimination of leukemia stem cells and blood stem cells
Hematopoietic stem cells from a healthy donor can help patients suffering from acute leukemia.
Computer simulations visualize how DNA is recognized to convert cells into stem cells
Researchers of the Hubrecht Institute (KNAW - The Netherlands) and the Max Planck Institute in Münster (Germany) have revealed how an essential protein helps to activate genomic DNA during the conversion of regular adult human cells into stem cells.
First events in stem cells becoming specialized cells needed for organ development
Cell biologists at the University of Toronto shed light on the very first step stem cells go through to turn into the specialized cells that make up organs.
Surprising research result: All immature cells can develop into stem cells
New sensational study conducted at the University of Copenhagen disproves traditional knowledge of stem cell development.
The development of brain stem cells into new nerve cells and why this can lead to cancer
Stem cells are true Jacks-of-all-trades of our bodies, as they can turn into the many different cell types of all organs.
Healthy blood stem cells have as many DNA mutations as leukemic cells
Researchers from the Princess Máxima Center for Pediatric Oncology have shown that the number of mutations in healthy and leukemic blood stem cells does not differ.
New method grows brain cells from stem cells quickly and efficiently
Researchers at Lund University in Sweden have developed a faster method to generate functional brain cells, called astrocytes, from embryonic stem cells.
NUS researchers confine mature cells to turn them into stem cells
Recent research led by Professor G.V. Shivashankar of the Mechanobiology Institute at the National University of Singapore and the FIRC Institute of Molecular Oncology in Italy, has revealed that mature cells can be reprogrammed into re-deployable stem cells without direct genetic modification -- by confining them to a defined geometric space for an extended period of time.
Researchers develop a new method for turning skin cells into pluripotent stem cells
Researchers at the University of Helsinki, Finland, and Karolinska Institutet, Sweden, have for the first time succeeded in converting human skin cells into pluripotent stem cells by activating the cell's own genes.
In mice, stem cells seem to work in fighting obesity! What about stem cells in humans?
This release aims to summarize the available literature in regard to the effect of Mesenchymal Stem Cells transplantation on obesity and related comorbidities from the animal model.
More Stem Cells News and Stem Cells Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Making Amends
What makes a true apology? What does it mean to make amends for past mistakes? This hour, TED speakers explore how repairing the wrongs of the past is the first step toward healing for the future. Guests include historian and preservationist Brent Leggs, law professor Martha Minow, librarian Dawn Wacek, and playwright V (formerly Eve Ensler).
Now Playing: Science for the People

#566 Is Your Gut Leaking?
This week we're busting the human gut wide open with Dr. Alessio Fasano from the Center for Celiac Research and Treatment at Massachusetts General Hospital. Join host Anika Hazra for our discussion separating fact from fiction on the controversial topic of leaky gut syndrome. We cover everything from what causes a leaky gut to interpreting the results of a gut microbiome test! Related links: Center for Celiac Research and Treatment website and their YouTube channel
Now Playing: Radiolab

The Flag and the Fury
How do you actually make change in the world? For 126 years, Mississippi has had the Confederate battle flag on their state flag, and they were the last state in the nation where that emblem remained "officially" flying.  A few days ago, that flag came down. A few days before that, it coming down would have seemed impossible. We dive into the story behind this de-flagging: a journey involving a clash of histories, designs, families, and even cheerleading. This show is a collaboration with OSM Audio. Kiese Laymon's memoir Heavy is here. And the Hospitality Flag webpage is here.