biology

PAX2

PAX2 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 PAX2 rather than just read about it. In short: Paired box gene 2, also known as Pax-2, is a protein which in humans is encoded by the PAX2 gene. Function The Pax Genes, or Paired-Box Containing Genes, play important roles in the development and proliferation of multiple cell lines, development of organs, and development and organization of the central nervous system.

Key takeaways

PAX2 belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect PAX2 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of PAX2 from memory before moving on to harder problems.

Reference excerpt

Paired box gene 2, also known as Pax-2, is a protein which in humans is encoded by the PAX2 gene.

Function The Pax Genes, or Paired-Box Containing Genes, play important roles in the development and proliferation of multiple cell lines, development of organs, and development and organization of the central nervous system. The transcription factor gene PAX2 is important in the regionalized embryological development of the central nervous system. In mammals, the brain is developed in three regions: the forebrain, midbrain, and the hindbrain. Concentration gradients of fibroblast growth factor 8 (FGF8) and Wingless-Type MMTV Integration Site Family, Member 1 (Wnt1) control expression of Pax-2 during development of the Mesencephalon, or midbrain. Similar patterning during embryological development can be observed in “basal chordates or ascidians,” in which organization of the central nervous system in ascidian larvae are also controlled by fibroblast growth factor genes. PAX2 encodes for the transcription factor which appears to be essential in the organization of the midbrain and hindbrain regions, and at the earliest can be detected on either side of the sulcus limitans, which separates motor and sensory nerve nuclei. PAX2 encodes paired box gene 2, one of many human homologues of the Drosophila melanogaster gene prd. The central feature of this transcription factor gene family is the conserved DNA-binding paired box domain. PAX2 is believed to be a target of transcriptional suppression by the tumor suppressor gene WT1. Pax 2 is a transcription factor controlled by the signaling molecules Wnt1 and Fgf8. Pax2 along with other transcription factors Pax5, Pax8, En1, and En 2 are expressed across the Otx2-Gbx2 boundary in the mid-hindbrain region. These transcription factors work with the signaling molecules Wnt1 and Fgf8 to maintain the MHB organizer. The MHB controls midbrain and cerebellum development. Pax2 is the earliest known gene to be expressed across the Otx2-Gbx2 boundary. It is first expressed in the late primitive streak stage and is expressed in a narrow ring centered at the MHB during somitogenesis. Transgene expression of the mid-hindbrain and developing kidney is directed by Pax2. There are three distinct MHB-specific enhancers in the upstream region of Pax2. Expression at the MHB from the four-somite stage onwards is directed by the two late enhancers in the proximal and distal regions of Pax2. The early enhancer located in the intermediate region activates the mid-hindbrain region of late gastrula embryos. The activation of Pax2, Pax5, and Pax8 is a conserved feature of all vertebrates.

Clinical significance Pathologically, Pax2 has been demonstrated to activate hepatocyte growth factor (HGF) gene promoter, and both have been indicated as playing a role in human prostate cancers. Mutations within PAX2 have been shown to result in optic nerve colobomas and renal hypoplasia. Alternative splicing of this gene results in multiple transcript variants. Pax2 and Pax8 are also necessary for the formation of the pronephros and subsequent kidney structures. Pax2 and Pax8 regulate the expression of Gata3. Without these genes mutations in the urogenital system arise. Pax2 misexpression is frequently observed in proliferative disorders of the kidney. For example, Pax2 is highly expressed in polycystic kidney disease (PKD), Wilms' tumor (WT), and renal cell carcinoma (RCC). Pax2 expression in these diseases appears fuel cell cycling, inhibit cell death, and confer resistance to chemotherapy. Due to its role in these diseases, Pax2 is an attractive therapeutic target and a number of methods for inhibiting its activity have been investigated. In fact, a small-molecule was recently identified with the ability to disrupt Pax2 mediated transcription by blocking Pax2 from binding to DNA.

Interactions PAX2 has been shown to interact with PAXIP1.

Illustrations

Worked examples

Example 1 — a first encounter with PAX2

Start with the simplest possible case. Write down what PAX2 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 PAX2 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 PAX2 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 PAX2

In research: PAX2 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 PAX2 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: PAX2 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Genes on human chromosome 10, Transcription factors, so understanding it makes those chapters shorter.
In everyday life: Look for PAX2 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 PAX2 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what PAX2 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 PAX2 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is PAX2 in simple terms?

Paired box gene 2, also known as Pax-2, is a protein which in humans is encoded by the PAX2 gene. Function The Pax Genes, or Paired-Box Containing Genes, play important roles in the development and proliferation of multiple cell lines, development of organs, and development and organization of the…

Why does PAX2 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 PAX2?

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 PAX2.