biology

Ribose-seq

Ribose-seq is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Ribose-seq rather than just read about it. In short: Ribose-seq is a mapping technique used in genetics research to determine the full profile of embedded ribonucleotides, specifically ribonucleoside monophosphates (rNMPs), in genomic DNA. Embedded ribonucleotides are thought to be the most common alteration to DNA in cells, and their presence in genomic DNA can affect genome stability.

Key takeaways

Ribose-seq belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Ribose-seq to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Ribose-seq from memory before moving on to harder problems.

Reference excerpt

Ribose-seq is a mapping technique used in genetics research to determine the full profile of embedded ribonucleotides, specifically ribonucleoside monophosphates (rNMPs), in genomic DNA. Embedded ribonucleotides are thought to be the most common alteration to DNA in cells, and their presence in genomic DNA can affect genome stability. As recent studies have suggested that ribonucleotides in mouse DNA may affect disease pathology, ribonucleotide incorporation in genomic DNA has become an important target of medical genetics research. Ribose-seq allows scientists to determine the precise location and type of ribonucleotides that have been incorporated into eukaryotic or prokaryotic DNA. The technique exploits the presence of the extra hydroxyl groups (OH) found in the 2' end of ribonucleotides, which can distort and destabilize DNA. The technique was developed through a collaboration with a group of researchers at the Georgia Institute of Technology including Francesca Storici and Kyung Duk Koh (now at the University of California San Francisco), and Jay Hesselberth at the University of Colorado Anschutz Medical School.

History Nucleic acids are the essential macromolecules that carry genetic information in all life forms. These biopolymers consist of nucleotide monomers, which are organic molecules that consist of a phosphate group, a nitrogen-containing base, and a five-carbon sugar (ribose in ribonucleotides and deoxyribose in deoxyribonucleotides). While ribonucleotides are typically located in ribonucleic acid (RNA), they can also be found in deoxyribonucleic acid (DNA). The first discovery of ribonucleoside monophosphates (rNMPs) embedded into DNA was in mitochondrial DNA from mouse and human cells in 1973 by Lawrence Grossman, Robert Watson, and Jerome Vinograd. In 2006, the presence of rNMPs were confirmed in nuclear DNA of Schizosaccharomyces pombe ("fission yeast"), and exploration in other species has continued since.

Incorporation of ribonucleotides into DNA Multiple studies have identified mechanisms by which ribonucleotides can be added to, removed from, or generated from DNA. Primarily, ribonucleotides are incorporated into DNA during the DNA synthesis process. To initiate DNA replication, short RNA primers synthesized on complementary DNA to allow for the subsequent binding and replication action of the primary replication enzymes, DNA polymerases. Typically, these primers are then removed by nuclease enzymes, RNases H or Flap Structure-specific Endonuclease 1 (FEN1). As such, there is a fairly substantial volume of transient rNMPs that are present in DNA in the form of RNA primers and then later removed. After DNA replication is initiated, rNMPs can be fully incorporated into DNA by DNA polymerases and this represents the major mechanism of ribonucleotide incorporation in DNA with over 1 ribonucleotide per 1,000 deoxyribonucleotides incorporated. The embedded rNMPs are often targeted for removal by the Ribonucleotide Excision Repair (RER) mechanism. However, if RER is not working properly, this can become a more persistent source of embedded rNMPs in DNA. Another mechanism by which rNMPs may arise in DNA is through oxidative stress, which alters the deoxyribose unit in DNA to a ribose. While the RER pathway is the most efficient process for removing rNMPs from DNA, ribonucleotides can also be removed through the 3'-5' exonuclease activity that is orchestrated by the proofreading activities of DNA polymerase during DNA replication. Additional rNMP removal methods include incisions that are mediated by the isomerase enzyme, topoisomerase I.

Consequences of ribonucleotides in DNA If not removed and replaced, ribonucleotides in DNA can have structural, chemical, and functional impacts on cellular processes. As first recognized by T.N. Jasihree et al. in 1993, the presence of ribonucleotides can alter the helical shape of DNA from B form to A form. This, in addition to a number of other chemical consequences, can impact the binding of proteins to DNA and have implications for processes such as chromatin dynamics, DNA replication, transcription, repair, and meiosis. Additionally, some DNA polymerases are unable to bypass embedded rNMPs during DNA replication, which is further exacerbated at sites with longer strands of rNMPs. This can cause replication stress which can potentially interfere with transcription, chromosome segregation, and future replication. Furthermore, certain byproducts or failures in the RER process can also potentially lead to DNA breaks, rearrangements, and genome instability.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Ribose-seq

Start with the simplest possible case. Write down what Ribose-seq claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Ribose-seq before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Ribose-seq ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Ribose-seq

In research: Ribose-seq appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Ribose-seq in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Ribose-seq is common in secondary-school and first-year university syllabi. It links to neighbouring topics Genetic mapping, Ribonucleases, so understanding it makes those chapters shorter.
In everyday life: Look for Ribose-seq outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Ribose-seq in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Ribose-seq means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Ribose-seq out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Ribose-seq in simple terms?

Why does Ribose-seq matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Ribose-seq?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Ribose-seq.