Daniel Sloan
Colorado State University-Fort Collins, CO·Genetics
Mitochondria and chloroplasts, the energy-producing compartments of plant and animal cells, began as free-living bacteria. They still carry their own small genomes and their own machinery for making proteins.
- Fields
Genetics
Ecology & Evolution
Plant Science & Agriculture
- Topics
mitochondrial DNA
mtDNA
mutation rate
- Grants
- 3 known grants, through May 2028
What they work on
- Test whether plant MSH1, a repair protein likely acquired from giant viruses, drives a new form of mismatch repair that cuts both DNA strands and then repairs the break by copying a template, keeping plant mitochondrial mutation rates exceptionally low.
- Test whether mitochondria have an unrecognized repair pathway resembling nucleotide excision repair, which cuts out bulky DNA damage, by analyzing damaged mtDNA fragments released after UV exposure in diverse eukaryotic model systems.
- Apply ultra-sensitive sequencing that detects rare new mutations and damaged bases at single-nucleotide resolution to compare mitochondrial DNA replication and repair across eukaryotes.
- Determine whether Silene mitochondria handle imported cytosolic tRNAs by evolving existing mitochondrial enzymes or by redirecting cytosolic aminoacyl-tRNA synthetases into mitochondria, using genomic, transcriptomic and experimental comparisons.
- Measure how changes in where enzymes are sent within the cell and in which tRNAs aminoacyl-tRNA synthetases recognize allow organellar genes to be lost in non-photosynthetic holoparasitic plants, using fluorescence microscopy, tRNA sequencing and test-tube aminoacylation assays.
- Determine how both roles of chloroplast tRNA-Glu, in protein translation and in building tetrapyrroles, are replaced in holoparasitic plants, allowing loss of the gene and eventually the whole chloroplast genome.
More about the research
That raises lasting questions. Why do some of these genomes mutate so fast while others barely change? And how can cells swap out ancient bacterial-like parts for their own versions without breaking essential functions? The lab's projects tackle these questions from two directions: how organelle DNA is copied and repaired, and how the molecules that translate organelle genes into proteins are lost and replaced over evolution.
Why it matters
High mutation rates in human mitochondrial DNA are a major cause of inherited and age-related diseases, yet why the rates are so high remains uncertain. By comparing DNA repair mechanisms across organisms, including plants that keep mutation rates extremely low, this work may clarify what drives harmful mitochondrial mutations in humans. The tRNA studies add basic understanding of how cells replace essential molecular parts and how organelles became fully integrated into eukaryotic cells.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Mechanisms of mitochondrial mutation rate variation across eukaryotes
NIH · Jun 2023 – May 2028
The effects of holoparasitism on plant organellar translation and tRNA metabolism
NSF · Sep 2023 – Aug 2027
Mitonuclear interactions and coevolution in the dynamic plant mitochondrial tRNA pool
NSF · Jan 2021 – Dec 2026
Closest labs
Jung-Hyun Min
Baylor University, TX·Biochemistry
Determine how the yeast damage sensor Rad4-Rad23-Rad33 (equivalent to human XPC-RAD23B-CETN2) and the unwinding machine TFIIH together open DNA around a lesion, using cryo-electron microscopy and crosslinking/mass spectrometry.
Ramiro Verdun
University of Miami, FL·Biochemistry
Determine how bypass of transcription-blocking DNA lesions by RNA Polymerase II, the enzyme that copies genes into RNA, disrupts the cellular response to ultraviolet radiation damage and disturbs normal cell function.
Michael Gruenstaeudl
Fort Hays State University, KS·Genetics
Build a tool that automatically links organelle genome records on GenBank to their original short-read sequencing data in the Sequence Read Archive (SRA), making the raw evidence behind each genome available for checking.
The school
Colorado State University-Fort Collins: 23 labs on PI Pages, $466M a year on research, 276 research doctorates a year.
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