Rachel Green (scientist)

Last updated
Rachel Green
BornOct 24, 1964
Alma mater
SpouseBrendan Cormack
Children3
Scientific career
Institutions
Thesis An in vitro genetic analysis of the group I self-splicing intron  (1992)

Rachel Green is an American biologist. She currently serves as a Bloomberg Distinguished Professor of molecular biology and genetics at the Johns Hopkins University School of Medicine. Her research focuses on ribosomes and their function in translation. Green has also been a Howard Hughes Medical Institute investigator since 2000.

Contents

Early life and education

Rachel Green was born on October 24, 1964. Green grew up in Rocky River, Ohio, where her mother was a chemistry teacher. [1] Green intended to study engineering in college, but changed her major to chemistry, earning a B.S. from the University of Michigan in 1986. She then earned a PhD in biochemistry from Harvard University in 1992, in the lab of Jack Szostak, where she studied RNA. [2]

She did postdoctoral research at University of California Santa Cruz in the lab of Harry Noller, researching the function of the ribosome in E. coli. [1] [3]

Career

Green joined the faculty at Johns Hopkins University School of Medicine in 1998. [1] In 2007 she became a full professor at Johns Hopkins. [4]

Green has been a Howard Hughes Medical Institute investigator since 2000. [5]

She was elected to the National Academy of Sciences in 2012, [6] to the National Academy of Medicine [7] in 2017, and to the American Academy of Arts and Sciences in 2019. [8]

Research

The focus of Green's laboratory is defining the molecular mechanisms that affect that accuracy of translation in bacteria, yeast, and higher eukaryotic systems. [9] After joining Johns Hopkins as a tenure-track assistant professor in 1998, Green began investigations into factors that control the translocation step of translation, where the ribosome moves forward over the messenger RNA (mRNA), prior to adding the next amino acid to the growing protein. [10] [11] Later, Green's research segued into studies on molecular factors and global mechanisms that affect translation accuracy. [12] In particular, Green and her colleagues found that certain nucleotides in transfer RNA (tRNA) molecules affect the ability of the ribosome to determine and select the correct tRNA in each step of translation. [13] Green's investigations into other aspects of translation quality control have included research into the mechanisms and effects of mRNA surveillance, in which mis-coded or nonfunctional mRNAs are subjected to degradation. [14] [15] [16]

Awards

Publications

Green has more than 16,000 citations in Google Scholar and an h-index of 69. [17]

Selected Publications

Personal life

Green's husband, Brendan Cormack, is also a geneticist at Johns Hopkins University. The couple has 3 children. [1]

Related Research Articles

<span class="mw-page-title-main">Ribosome</span> Synthesizes proteins in cells

Ribosomes are macromolecular machines, found within all cells, that perform biological protein synthesis. Ribosomes link amino acids together in the order specified by the codons of messenger RNA molecules to form polypeptide chains. Ribosomes consist of two major components: the small and large ribosomal subunits. Each subunit consists of one or more ribosomal RNA molecules and many ribosomal proteins. The ribosomes and associated molecules are also known as the translational apparatus.

<span class="mw-page-title-main">Translation (biology)</span> Cellular process of protein synthesis

In biology, translation is the process in living cells in which proteins are produced using RNA molecules as templates. The generated protein is a sequence of amino acids. This sequence is determined by the sequence of nucleotides in the RNA. The nucleotides are considered three at a time. Each such triple results in addition of one specific amino acid to the protein being generated. The matching from nucleotide triple to amino acid is called the genetic code. The translation is performed by a large complex of functional RNA and proteins called ribosomes. The entire process is called gene expression.

An internal ribosome entry site, abbreviated IRES, is an RNA element that allows for translation initiation in a cap-independent manner, as part of the greater process of protein synthesis. Initiation of eukaryotic translation nearly always occurs at and is dependent on the 5' cap of mRNA molecules, where the translation initiation complex forms and ribosomes engage the mRNA. IRES elements, however allow ribosomes to engage the mRNA and begin translation independently of the 5' cap.

<span class="mw-page-title-main">Start codon</span> First codon of a messenger RNA translated by a ribosome

The start codon is the first codon of a messenger RNA (mRNA) transcript translated by a ribosome. The start codon always codes for methionine in eukaryotes and archaea and a N-formylmethionine (fMet) in bacteria, mitochondria and plastids.

<span class="mw-page-title-main">Venki Ramakrishnan</span> British-American structural biologist (born 1952)

Venkatraman Ramakrishnan is a British-American structural biologist. He shared the 2009 Nobel Prize in Chemistry with Thomas A. Steitz and Ada Yonath for research on the structure and function of ribosomes.

The Kozak consensus sequence is a nucleic acid motif that functions as the protein translation initiation site in most eukaryotic mRNA transcripts. Regarded as the optimum sequence for initiating translation in eukaryotes, the sequence is an integral aspect of protein regulation and overall cellular health as well as having implications in human disease. It ensures that a protein is correctly translated from the genetic message, mediating ribosome assembly and translation initiation. A wrong start site can result in non-functional proteins. As it has become more studied, expansions of the nucleotide sequence, bases of importance, and notable exceptions have arisen. The sequence was named after the scientist who discovered it, Marilyn Kozak. Kozak discovered the sequence through a detailed analysis of DNA genomic sequences.

Gene structure is the organisation of specialised sequence elements within a gene. Genes contain most of the information necessary for living cells to survive and reproduce. In most organisms, genes are made of DNA, where the particular DNA sequence determines the function of the gene. A gene is transcribed (copied) from DNA into RNA, which can either be non-coding (ncRNA) with a direct function, or an intermediate messenger (mRNA) that is then translated into protein. Each of these steps is controlled by specific sequence elements, or regions, within the gene. Every gene, therefore, requires multiple sequence elements to be functional. This includes the sequence that actually encodes the functional protein or ncRNA, as well as multiple regulatory sequence regions. These regions may be as short as a few base pairs, up to many thousands of base pairs long.

A release factor is a protein that allows for the termination of translation by recognizing the termination codon or stop codon in an mRNA sequence. They are named so because they release new peptides from the ribosome.

<span class="mw-page-title-main">Elongation factor</span> Proteins functioning in translation

Elongation factors are a set of proteins that function at the ribosome, during protein synthesis, to facilitate translational elongation from the formation of the first to the last peptide bond of a growing polypeptide. Most common elongation factors in prokaryotes are EF-Tu, EF-Ts, EF-G. Bacteria and eukaryotes use elongation factors that are largely homologous to each other, but with distinct structures and different research nomenclatures.

<span class="mw-page-title-main">EF-Tu</span> Prokaryotic elongation factor

EF-Tu is a prokaryotic elongation factor responsible for catalyzing the binding of an aminoacyl-tRNA (aa-tRNA) to the ribosome. It is a G-protein, and facilitates the selection and binding of an aa-tRNA to the A-site of the ribosome. As a reflection of its crucial role in translation, EF-Tu is one of the most abundant and highly conserved proteins in prokaryotes. It is found in eukaryotic mitochondria as TUFM.

Eukaryotic initiation factors (eIFs) are proteins or protein complexes involved in the initiation phase of eukaryotic translation. These proteins help stabilize the formation of ribosomal preinitiation complexes around the start codon and are an important input for post-transcription gene regulation. Several initiation factors form a complex with the small 40S ribosomal subunit and Met-tRNAiMet called the 43S preinitiation complex. Additional factors of the eIF4F complex recruit the 43S PIC to the five-prime cap structure of the mRNA, from which the 43S particle scans 5'-->3' along the mRNA to reach an AUG start codon. Recognition of the start codon by the Met-tRNAiMet promotes gated phosphate and eIF1 release to form the 48S preinitiation complex, followed by large 60S ribosomal subunit recruitment to form the 80S ribosome. There exist many more eukaryotic initiation factors than prokaryotic initiation factors, reflecting the greater biological complexity of eukaryotic translation. There are at least twelve eukaryotic initiation factors, composed of many more polypeptides, and these are described below.

<span class="mw-page-title-main">5.8S ribosomal RNA</span> RNA component of the large subunit of the eukaryotic ribosome

In molecular biology, the 5.8S ribosomal RNA is a non-coding RNA component of the large subunit of the eukaryotic ribosome and so plays an important role in protein translation. It is transcribed by RNA polymerase I as part of the 45S precursor that also contains 18S and 28S rRNA. Its function is thought to be in ribosome translocation. It is also known to form covalent linkage to the p53 tumour suppressor protein. 5.8S rRNA can be used as a reference gene for miRNA detection. The 5.8S ribosomal RNA is used to better understand other rRNA processes and pathways in the cell.

Ribosomal particles are denoted according to their sedimentation coefficients in Svedberg units. The 60S subunit is the large subunit of eukaryotic 80S ribosomes, with the other major component being the eukaryotic small ribosomal subunit (40S). It is structurally and functionally related to the 50S subunit of 70S prokaryotic ribosomes. However, the 60S subunit is much larger than the prokaryotic 50S subunit and contains many additional protein segments, as well as ribosomal RNA expansion segments.

<span class="mw-page-title-main">EF-G</span> Prokaryotic elongation factor

EF-G is a prokaryotic elongation factor involved in mRNA translation. As a GTPase, EF-G catalyzes the movement (translocation) of transfer RNA (tRNA) and messenger RNA (mRNA) through the ribosome.

The eukaryotic small ribosomal subunit (40S) is the smaller subunit of the eukaryotic 80S ribosomes, with the other major component being the large ribosomal subunit (60S). The "40S" and "60S" names originate from the convention that ribosomal particles are denoted according to their sedimentation coefficients in Svedberg units. It is structurally and functionally related to the 30S subunit of 70S prokaryotic ribosomes. However, the 40S subunit is much larger than the prokaryotic 30S subunit and contains many additional protein segments, as well as rRNA expansion segments.

<span class="mw-page-title-main">Eukaryotic ribosome</span> Large and complex molecular machine

Ribosomes are a large and complex molecular machine that catalyzes the synthesis of proteins, referred to as translation. The ribosome selects aminoacylated transfer RNAs (tRNAs) based on the sequence of a protein-encoding messenger RNA (mRNA) and covalently links the amino acids into a polypeptide chain. Ribosomes from all organisms share a highly conserved catalytic center. However, the ribosomes of eukaryotes are much larger than prokaryotic ribosomes and subject to more complex regulation and biogenesis pathways. Eukaryotic ribosomes are also known as 80S ribosomes, referring to their sedimentation coefficients in Svedberg units, because they sediment faster than the prokaryotic (70S) ribosomes. Eukaryotic ribosomes have two unequal subunits, designated small subunit (40S) and large subunit (60S) according to their sedimentation coefficients. Both subunits contain dozens of ribosomal proteins arranged on a scaffold composed of ribosomal RNA (rRNA). The small subunit monitors the complementarity between tRNA anticodon and mRNA, while the large subunit catalyzes peptide bond formation.

The P-site is the second binding site for tRNA in the ribosome. The other two sites are the A-site (aminoacyl), which is the first binding site in the ribosome, and the E-site (exit), the third. During protein translation, the P-site holds the tRNA which is linked to the growing polypeptide chain. When a stop codon is reached, the peptidyl-tRNA bond of the tRNA located in the P-site is cleaved releasing the newly synthesized protein. During the translocation step of the elongation phase, the mRNA is advanced by one codon, coupled to movement of the tRNAs from the ribosomal A to P and P to E sites, catalyzed by elongation factor EF-G.

<span class="mw-page-title-main">Ribosomal pause</span> Queueing or stacking of ribosomes during translation of the nucleotide sequence of mRNA transcripts

Ribosomal pause refers to the queueing or stacking of ribosomes during translation of the nucleotide sequence of mRNA transcripts. These transcripts are decoded and converted into an amino acid sequence during protein synthesis by ribosomes. Due to the pause sites of some mRNA's, there is a disturbance caused in translation. Ribosomal pausing occurs in both eukaryotes and prokaryotes. A more severe pause is known as a ribosomal stall.

Marilyn S. Kozak is an American professor of biochemistry at the Robert Wood Johnson Medical School. She was previously at the University of Medicine and Dentistry of New Jersey before the school was merged. She was awarded a PhD in microbiology by Johns Hopkins University studying the synthesis of the Bacteriophage MS2, advised by Daniel Nathans.

<span class="mw-page-title-main">Sandra Wolin</span> American microbiologist and physician-scientist

Sandra Lynn Wolin is an American microbiologist and physician-scientist specialized in biogenesis, function, and turnover of non-coding RNA. She is chief of the RNA Biology Laboratory at the National Cancer Institute.

References

  1. 1 2 3 4 April 17, Katie Pearce / Published (17 April 2017). "Johns Hopkins biologist, geneticist Rachel Green named Bloomberg Distinguished Professor". The Hub. Retrieved 25 April 2019.{{cite web}}: CS1 maint: numeric names: authors list (link)
  2. ↑ "Rachel Green, Ph.D." www.hopkinsmedicine.org. Retrieved 25 April 2019.
  3. ↑ "Rachel Green Inside Look". HHMI.org. Retrieved 25 April 2019.
  4. ↑ "Rachel Green". Department of Biology. Retrieved 2020-04-22.
  5. ↑ "Rachel Green". HHMI.org. Retrieved 25 April 2019.
  6. ↑ "Rachel Green". www.nasonline.org. Retrieved 25 April 2019.
  7. ↑ "National Academy of Medicine Elects 80 New Members". National Academy of Medicine. 2017-10-16. Retrieved 2020-05-25.
  8. ↑ "Three Johns Hopkins Scientists Elected to American Academy of Arts and Sciences". Johns Hopkins Medicine Newsroom. 18 April 2019. Retrieved 25 April 2019.
  9. ↑ Schuller, Anthony P.; Green, Rachel (2018). "Roadblocks and resolutions in eukaryotic translation". Nature Reviews Molecular Cell Biology. 19 (8): 526–541. doi:10.1038/s41580-018-0011-4. ISSN   1471-0080. PMC   6054806 . PMID   29760421.
  10. ↑ Green, Rachel (2000-05-15). "Ribosomal translocation: EF-G turns the crank". Current Biology. 10 (10): R369–R373. doi: 10.1016/S0960-9822(00)00481-4 . ISSN   0960-9822. PMID   10837219.
  11. ↑ Cukras, Anthony R.; Southworth, Daniel R.; Brunelle, Julie L.; Culver, Gloria M.; Green, Rachel (2003-08-01). "Ribosomal Proteins S12 and S13 Function as Control Elements for Translocation of the mRNA:tRNA Complex". Molecular Cell. 12 (2): 321–328. doi: 10.1016/S1097-2765(03)00275-2 . ISSN   1097-2765. PMID   14536072.
  12. ↑ Cochella, Luisa; Green, Rachel (July 2005). "Fidelity in protein synthesis". Current Biology. 15 (14): R536–R540. doi: 10.1016/j.cub.2005.07.018 .
  13. ↑ Cochella, L. (2005-05-20). "An Active Role for tRNA in Decoding Beyond Codon:Anticodon Pairing". Science. 308 (5725): 1178–1180. doi:10.1126/science.1111408. ISSN   0036-8075. PMC   1687177 . PMID   15905403.
  14. ↑ Djuranovic, S.; Nahvi, A.; Green, R. (2011-02-04). "A Parsimonious Model for Gene Regulation by miRNAs". Science. 331 (6017): 550–553. doi:10.1126/science.1191138. ISSN   0036-8075. PMC   3955125 . PMID   21292970.
  15. ↑ Shoemaker, Christopher J; Green, Rachel (June 2012). "Translation drives mRNA quality control". Nature Structural & Molecular Biology. 19 (6): 594–601. doi:10.1038/nsmb.2301. ISSN   1545-9993. PMC   4299859 . PMID   22664987.
  16. ↑ Simms, Carrie L.; Thomas, Erica N.; Zaher, Hani S. (2017). "Ribosome-based quality control of mRNA and nascent peptides". WIREs RNA. 8 (1): e1366. doi:10.1002/wrna.1366. ISSN   1757-7012. PMC   5116004 . PMID   27193249.
  17. ↑ "Rachel Green". scholar.google.com. Retrieved 2021-05-11.
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