biology

Homeobox protein NANOG

Homeobox protein NANOG 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 Homeobox protein NANOG rather than just read about it. In short: Homeobox protein NANOG (hNanog) is a transcriptional factor that helps embryonic stem cells (ESCs) maintain pluripotency by suppressing cell determination factors. hNanog is encoded in humans by the NANOG gene. Several types of cancer are associated with NANOG.

Key takeaways

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

Reference excerpt

Homeobox protein NANOG (hNanog) is a transcriptional factor that helps embryonic stem cells (ESCs) maintain pluripotency by suppressing cell determination factors. hNanog is encoded in humans by the NANOG gene. Several types of cancer are associated with NANOG.

Etymology The name NANOG derives from Tír na nÓg (Irish for "Land of the Young"), a name given to the Celtic Otherworld in Irish and Scottish mythology.

Structure The human hNanog protein coded by the NANOG gene, consists of 305 amino acids and possesses 3 functional domains: the N-terminal domain, the C- terminal domain, and the conserved homeodomain motif. The homeodomain region facilitates DNA binding. The NANOG is located on chromosome 12, and the mRNA contains a 915 bp open reading frame (ORF) with 4 exons and 3 introns. The N-terminal region of hNanog is rich in serine, threonine and proline residues, and the C-terminus contains a tryptophan-rich domain. The homeodomain in hNANOG ranges from residues 95 to 155. There are also additional NANOG genes (NANOG2, NANOG p8) which potentially affect ESCs' differentiation. Scientists have shown that NANOG is fundamental for self-renewal and pluripotency, and NANOG p8 is highly expressed in cancer cells.

Function

NANOG is a transcription factor in embryonic stem cells (ESCs) and is thought to be a key factor in maintaining pluripotency. NANOG is thought to function in concert with other factors such as POU5F1 (Oct-4) and SOX2 to establish ESC identity. These cells offer an important area of study because of their ability to maintain pluripotency. In other words, these cells have the ability to become virtually any cell of any of the three germ layers (endoderm, ectoderm, mesoderm). It is for this reason that understanding the mechanisms that maintain a cell's pluripotency is critical for researchers to understand how stem cells work, and may lead to future advances in treating degenerative diseases. NANOG has been described to be expressed in the posterior side of the epiblast at the onset of gastrulation. There, NANOG has been implicated in inhibiting embryonic hematopoiesis by repressing the expression of the transcription factor Tal1. In this embryonic stage, NANOG represses Pou3f1, a transcription factor crucial for the anterior-posterior axis formation. Analysis of arrested embryos demonstrated that embryos express pluripotency marker genes such as POU5F1, NANOG and Rex1. Derived human ESC lines also expressed specific pluripotency markers:

TRA-1-60 TRA-1-81 SSEA4 alkaline phosphatase TERT Rex1 These markers allowed for the differentiation in vitro and in vivo conditions into derivatives of all three germ layers. POU5F1, TDGF1 (CRIPTO), SALL4, LECT1, and BUB1 are also related genes all responsible for self-renewal and pluripotent differentiation. The NANOG protein has been found to be a transcriptional activator for the Rex1 promoter, playing a key role in sustaining Rex1 expression. Knockdown of NANOG in embryonic stem cells results in a reduction of Rex1 expression, while forced expression of NANOG stimulates Rex1 expression. Besides the effects of NANOG in the embryonic stages of life, ectopic expression of NANOG in the adult stem cells can restore the proliferation and differentiation potential that is lost due to organismal aging or cellular senescence.

Clinical significance

Cancer NANOG is highly expressed in cancer stem cells and may thus function as an oncogene to promote carcinogenesis. High expression of NANOG correlates with poor survival in cancer patients. Recent research has shown that the localization of NANOG and other transcription factors have potential consequences on cellular function. Experimental evidence has shown that the level of NANOG p8 expression is elevated specially in cancer cells, which mean that NANOG p8 gene is a critical member in (CSCs) Cancer stem cells, so knocking it down could reduce the cancer malignancy.

Diagnostics NANOG p8 gene has been evaluated as a prognostic and predictive cancer biomarker.

Cancer stem cells Nanog is a transcription factor that controls both self-renewal and pluripotency of embryonic stem cells. Similarly, the expression of Nanog family proteins is increased in many types of cancer and correlates with a worse prognosis.

Evolution Humans and chimpanzees share ten NANOG pseudogenes (NanogP2-P11) during evaluation, two of them are located on the X chromosome and they characterized by the 5’ promoter sequences and the absence of introns as a result of mRNA retrotransposition all in the same places: one duplication pseudogene and nine retropseudogenes. Of the nine shared NANOG retropseudogenes, two lack the poly-(A) tails characteristic of most retropseudogenes, indicating that copying errors occurred during their creation. Due to the high improbability that the same pseudogenes (copying errors included) would exist in the same places in two unrelated genomes, evolutionary biologists point to NANOG and its pseudogenes as providing evidence of common descent between humans and chimpanzees.

See also Enhancer Histone Oct-4 Pribnow box Promoter RNA polymerase Brachyury Transcription factors Gene regulatory network Bioinformatics

References

Illustrations

Worked examples

Example 1 — a first encounter with Homeobox protein NANOG

Start with the simplest possible case. Write down what Homeobox protein NANOG 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 Homeobox protein NANOG 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 Homeobox protein NANOG 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 Homeobox protein NANOG

In research: Homeobox protein NANOG 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 Homeobox protein NANOG 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: Homeobox protein NANOG is common in secondary-school and first-year university syllabi. It links to neighbouring topics Gene expression, Genes on human chromosome 12, Oncology, so understanding it makes those chapters shorter.
In everyday life: Look for Homeobox protein NANOG 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 Homeobox protein NANOG in 20 minutes

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Frequently asked questions

What is Homeobox protein NANOG in simple terms?

Why does Homeobox protein NANOG 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 Homeobox protein NANOG?

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 Homeobox protein NANOG.