# Steven Jacobsen
Steven E. Jacobsen is an American plant biologist and geneticist at the [University of California, Los Angeles](https://www.edgepedia.org/university-of-california-los-angeles) (UCLA), known for pioneering the molecular analysis of epigenetic gene silencing in plants; he has been a [Howard Hughes Medical Institute](https://www.edgepedia.org/howard-hughes-medical-institute) (HHMI) Investigator since 2005 and was elected to the National Academy of Sciences in 2011 in the Plant, Soil, and Microbial Sciences section.[1](https://www.nasonline.org/directory-entry/steven-e-jacobsen-c0loie/) • [2](https://orcid.org/0000-0001-9483-138X) He is Professor of Molecular, Cell and Developmental Biology at UCLA, where his laboratory dissects how [DNA methylation](https://www.edgepedia.org/dna-methylation), histone methylation, and small RNAs combine to silence genes and transposons in the model plant *Arabidopsis thaliana*.[2](https://orcid.org/0000-0001-9483-138X) • [1](https://www.nasonline.org/directory-entry/steven-e-jacobsen-c0loie/)
| Key facts | |
|---|---|
| **Field** | Plant epigenetics; DNA methylation, histone methylation, small RNAs |
| **Position** | Professor of Molecular, Cell, and Developmental Biology, UCLA (since July 1998); HHMI Investigator (since 2005)[2](https://orcid.org/0000-0001-9483-138X) |
| **Education** | B.S. Plant Biology, Cal Poly San Luis Obispo (1987); Ph.D. Plant Biology, University of Minnesota (1993); Caltech postdoc (to 1998)[2](https://orcid.org/0000-0001-9483-138X) |
| **Known for** | Purely epigenetic mutants; defining the RNA-directed DNA methylation pathway; KRYPTONITE discovery; genome-wide methylation methods[3](https://scholar.google.co.uk/citations?hl=en&oi=sra&user=_bACLswAAAAJ) • [7](https://www.amacad.org/person/steven-e-jacobsen) • [1](https://www.nasonline.org/directory-entry/steven-e-jacobsen-c0loie/) |
| **Honours** | NAS (2011); American Academy of Arts and Sciences (2016); Beckman and Searle young investigator awards[1](https://www.nasonline.org/directory-entry/steven-e-jacobsen-c0loie/) • [4](https://www.doe-mbi.ucla.edu/info/steven-e-jacobsen/) |
| **Output** | Over 230 research articles and reviews[4](https://www.doe-mbi.ucla.edu/info/steven-e-jacobsen/) |
| **Translation** | Cofounder of Inari Agriculture; plant gene-editing and CRISPR-based targeted epigenetics tools[4](https://www.doe-mbi.ucla.edu/info/steven-e-jacobsen/) • [5](https://www.terranabio.com/team-members/steve-jacobsen) |
## Education and career
Jacobsen completed a B.S. in Plant Biology at [California Polytechnic State University, San Luis Obispo](https://www.edgepedia.org/california-polytechnic-state-university-san-luis-obispo) in June 1987, and a Ph.D. in Plant Biology at the [University of Minnesota](https://www.edgepedia.org/university-of-minnesota), Twin Cities in October 1993.[2](https://orcid.org/0000-0001-9483-138X) He then trained in plant developmental genetics as a postdoctoral researcher at the [California Institute of Technology](https://www.edgepedia.org/california-institute-of-technology), finishing in July 1998.[2](https://orcid.org/0000-0001-9483-138X)
He joined UCLA as a professor of Molecular, Cell, and Developmental Biology on July 1, 1998, and has held that position since; in 2005 he became an Investigator of the Howard Hughes Medical Institute.[2](https://orcid.org/0000-0001-9483-138X) His UCLA profile counts more than 230 research articles and reviews, and the laboratory's own publication list runs to at least 242 entries.[4](https://www.doe-mbi.ucla.edu/info/steven-e-jacobsen/) • [6](https://research.mcdb.ucla.edu/Jacobsen/LabWebSite/P_Publications.php)
## Research and contributions
**Purely epigenetic mutants.** Early in his career Jacobsen was among the first to describe *Arabidopsis* mutants with heritable changes in DNA methylation and gene expression that occur without any change in DNA sequence, providing direct genetic proof that epigenetic states can be inherited across generations.[7](https://www.amacad.org/person/steven-e-jacobsen)
**How each methylation context is controlled.** The National Academy of Sciences member directory summarizes his laboratory's central findings on the three sequence contexts of plant DNA methylation.[1](https://www.nasonline.org/directory-entry/steven-e-jacobsen-c0loie/)
CG methylation is maintained by MET1, a homolog of mammalian DNMT1, together with VIM1, a plant counterpart of the mammalian UHRF1 protein.[1](https://www.nasonline.org/directory-entry/steven-e-jacobsen-c0loie/)
CHG methylation is inherited through a positive feedback loop between the two epigenetic marks: the histone H3 lysine 9 (H3K9) methyltransferase KRYPTONITE binds directly to CHG-methylated DNA, and the CHG methyltransferase CMT3 binds directly to methylated histone H3 tails, so each mark recruits the enzyme that writes the other.[1](https://www.nasonline.org/directory-entry/steven-e-jacobsen-c0loie/)
Initiation and CHH methylation require the methyltransferase DRM2, a homolog of mammalian Dnmt3, which is guided by 24-nucleotide small interfering RNAs and the RNA silencing proteins Pol IV, RDR2, DCL3, Pol V, and AGO4; CHH methylation is maintained by continual DRM2 and small-RNA targeting rather than by copying of an existing strand.[1](https://www.nasonline.org/directory-entry/steven-e-jacobsen-c0loie/) This RNA-guided pathway, [RNA-directed DNA methylation](https://www.edgepedia.org/rna-directed-dna-methylation), allows the plant to silence transposons and repeats at locations specified by small RNAs. Beyond DNA methylation, the laboratory studies how these marks converge in self-reinforcing pathways for stable, heritable gene silencing, using genetics, genomics, and biochemistry in *Arabidopsis* and, extending its reach, in the mouse, as in its 2016 PNAS study showing that mouse MORC3 is a GHKL ATPase that localizes to H3K4me3-marked chromatin.[8](https://www.mcdb.ucla.edu/indivfaculty/?faculty=Jacobsen)
**Genome-wide methods.** Jacobsen developed methods for genome-wide analysis of DNA methylation, tools now used across organisms; his laboratory also develops tools for gene editing in plants and for targeted epigenetics using CRISPR systems.[7](https://www.amacad.org/person/steven-e-jacobsen) • [4](https://www.doe-mbi.ucla.edu/info/steven-e-jacobsen/)
## Key publications
**Interplay between two epigenetic marks (Current Biology, 2002).** This paper, co-authored by Jacobsen, asked whether DNA methylation can direct histone H3 methylation, the reverse of the then-known relationship in *Neurospora*, where H3K9 methylation is required for all known DNA methylation.[9](https://doi.org/10.1016/s0960-9822(02)00976-4) Using chromatin immunoprecipitation, the authors showed that *Arabidopsis* heterochromatin carries H3K9 methylation that depends on the KRYPTONITE and DDM1 genes, homologs of SU(VAR)3-9 and SWI2/SNF2 respectively.[9](https://doi.org/10.1016/s0960-9822(02)00976-4) The decisive result was directional: a decrease in DNA methylation did not cause a loss of H3K9 methylation; loss of H3K9 methylation occurred only at loci where transcription was derepressed, consistent with reactivation followed by deposition of unmethylated nucleosomes.[9](https://doi.org/10.1016/s0960-9822(02)00976-4) The conclusion, that DNA methylation does not control H3K9 methylation, fixed the direction of causality in this feedback system. iCite records about 372 citations for the paper.[9](https://doi.org/10.1016/s0960-9822(02)00976-4)
**KRYPTONITE (Nature, 2002).** In the same year, Jackson, Lindroth, Cao, and Jacobsen published "Control of CpNpG DNA methylation by the KRYPTONITE histone H3 methyltransferase" in *Nature* 416:556-560, the paper that identified the H3K9 methyltransferase now understood to sit at the heart of the CHG feedback loop.[3](https://scholar.google.co.uk/citations?hl=en&oi=sra&user=_bACLswAAAAJ)
**Review synthesis (Nature Reviews Genetics, 2010).** Jacobsen co-authored "Establishing, maintaining and modifying DNA methylation patterns in plants and animals" (*Nature Reviews Genetics* 11:204-220).[3](https://scholar.google.co.uk/citations?hl=en&oi=sra&user=_bACLswAAAAJ)
The supplied publication list also contains a cluster of [Kaiser Permanente](https://www.edgepedia.org/kaiser-permanente) health-services and epidemiology papers (COVID-19 care utilization, varicella-zoster genotyping, PSA screening trends, and others) attributed to a different, same-named researcher; none of those papers appear under the UCLA plant biologist's ORCID record, which lists only plant-biology employment and education.[2](https://orcid.org/0000-0001-9483-138X)
## Honours and recognition
Jacobsen was elected to the National Academy of Sciences in 2011, with primary Section 62 (Plant, Soil, and Microbial Sciences) and secondary Section 25 (Plant Biology); the 2011 class comprised 72 new members and 18 foreign associates.[1](https://www.nasonline.org/directory-entry/steven-e-jacobsen-c0loie/) • [10](https://www.eurekalert.org/news-releases/821093) He was elected to the American Academy of Arts and Sciences in 2016 and earlier received the Beckman and Searle young investigator awards.[4](https://www.doe-mbi.ucla.edu/info/steven-e-jacobsen/) His HHMI appointment as Investigator has continued since 2005.[2](https://orcid.org/0000-0001-9483-138X)
## Ventures and translational work
Jacobsen is a cofounder of Inari Agriculture, a company applying plant genomics to crop improvement, an instance of his laboratory's basic epigenetics work feeding into agriculture.[4](https://www.doe-mbi.ucla.edu/info/steven-e-jacobsen/) • [5](https://www.terranabio.com/team-members/steve-jacobsen) Within academia, the laboratory develops tools for gene editing in plants, as well as tools for targeted epigenetics using CRISPR systems.[4](https://www.doe-mbi.ucla.edu/info/steven-e-jacobsen/) The sources reviewed here do not document patent holdings or other companies, and his recent (2024 to 2026) publication titles were not retrievable in the reviewed sources.[6](https://research.mcdb.ucla.edu/Jacobsen/LabWebSite/P_Publications.php)
## Disambiguation: other researchers named Steven Jacobsen
A prolific health-services researcher and epidemiologist named Steven Jacobsen has published extensively with Kaiser Permanente Southern California on topics including pandemic health-care utilization (about 101 iCite citations), varicella-zoster virus genotyping, chronic kidney disease and renin levels, mortality trends, [HPV vaccine](https://www.edgepedia.org/hpv-vaccine) completion in boys, and prostate cancer screening.[11](https://doi.org/10.2196/26558) • [12](https://doi.org/10.1099/jgv.0.000772) The two are distinct people: the UCLA plant biologist's ORCID record (0000-0001-9483-138X) contains only plant-biology training, a UCLA professorship, and HHMI membership, and none of the Kaiser Permanente papers, while the NAS directory confirms the academy member is the UCLA molecular biologist.[2](https://orcid.org/0000-0001-9483-138X) • [1](https://www.nasonline.org/directory-entry/steven-e-jacobsen-c0loie/)
## References
1. Steven E. Jacobsen, NAS Member Directory, National Academy of Sciences. https://www.nasonline.org/directory-entry/steven-e-jacobsen-c0loie/
2. Steven Jacobsen (0000-0001-9483-138X), ORCID. https://orcid.org/0000-0001-9483-138X
3. Steven E. Jacobsen, Google Scholar profile. https://scholar.google.co.uk/citations?hl=en&oi=sra&user=_bACLswAAAAJ
4. Steven E. Jacobsen, UCLA-DOE Institute. https://www.doe-mbi.ucla.edu/info/steven-e-jacobsen/
5. Steve Jacobsen, Ph.D., Terrana Biosciences team page. https://www.terranabio.com/team-members/steve-jacobsen
6. Jacobsen Lab at UCLA, Publications. https://research.mcdb.ucla.edu/Jacobsen/LabWebSite/P_Publications.php
7. Steven E. Jacobsen, American Academy of Arts & Sciences. https://www.amacad.org/person/steven-e-jacobsen
8. Steve Jacobsen, UCLA MCDB faculty. https://www.mcdb.ucla.edu/indivfaculty/?faculty=Jacobsen
9. Interplay between two epigenetic marks. DNA methylation and histone H3 lysine 9 methylation, Current Biology (2002). https://doi.org/10.1016/s0960-9822(02)00976-4
10. ASPB members elected to National Academy of Sciences, EurekAlert. https://www.eurekalert.org/news-releases/821093
11. Impact of the COVID-19 Pandemic on Health Care Utilization in a Large Integrated Health Care System, J Med Internet Res (2021). https://doi.org/10.2196/26558
12. Revisiting the genotyping scheme for varicella-zoster viruses based on whole-genome comparisons, J Gen Virol (2017). https://doi.org/10.1099/jgv.0.000772
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*Topic: Encyclopedia › Life and health › Life and health scientists › Life scientists › Researchers in developmental biology, stem cells, and plant biology › Epigenetics and gene regulation in development*
*Initially written Sep 17, 2026 · Edited: Oct 15, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license