FACTOID # 31: Almost half of Ecuador is subject to environmental protection.
 
 Home   Encyclopedia   Statistics   Countries A-Z   Flags   Maps   Education   Forum   FAQ   About 
 
WHAT'S NEW
RECENT ARTICLES
More Recent Articles »
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > HRAS

HRAS is a human gene that provides instructions for making a protein that is involved in cell division. In a process called signal transduction, the protein relays signals from outside the cell to the cell nucleus and instructs the cell to grow or divide. The HRAS protein is a GTPase, which means it converts a molecule called GTP into another molecule called GDP. The protein acts like a switch; to transmit signals, the HRAS protein must be turned on (activated) by binding to GTP. The HRAS protein is turned off (inactivated) when it converts GTP to GDP. When the protein is bound to GDP, it does not relay signals to the cell nucleus. Trinomial name Homo sapiens sapiens Linnaeus, 1758 Humans, or human beings, are biologically classified as bipedal primates belonging to the mammalian species Homo sapiens (Latin for wise man or thinking man) under the family Hominidae (the great apes). ... This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... GTPases are a large family of enzymes that can bind and hydrolyze GTP. The GTP binding and hydrolysis takes place in the highly conserved G domain common to all GTPases. ... GTP (also known as guanylyl imidodiphosphate, guanosine-5-triphosphate, or guanosine triphosphate) is a chemical compound (nucleotide) that is incorporated into the growing RNA chain during synthesis of RNA and used as a source of energy during synthesis of proteins. ...


HRAS is a member of a class of genes called oncogenes. When mutated, oncogenes have the potential to cause normal cells to become cancerous. HRAS is in the Ras family, which also includes two other oncogenes: KRAS2 and NRAS. The protein products of these three genes are GTPases. These proteins play important roles in cell division, cell specialization (the process by which cells mature to carry out specific functions), and controlled cell death (apoptosis). An oncogene is a modified gene that increases the malignancy of a tumor cell. ... Apoptosis In biology, apoptosis (from the Greek words apo = from and ptosis = falling, commonly pronounced ap-a-tow-sis[1]) is one of the main types of programmed cell death (PCD). ...


The HRAS gene is located on the short (p) arm of chromosome 11 at position 15.5, from base pair 522,241 to base pair 525,549. Chromosome 11 is one of the 23 pairs of chromosomes in humans. ... Headline text this website sucks your mothers dickIn molecular biology, two nucleotides on opposite complementary DNA or RNA strands that are connected via hydrogen bonds are called a base pair (often abbreviated bp). ...


Related conditions

Costello syndrome: At least five inherited mutations in the HRAS gene have been identified in people with Costello syndrome. Each of these mutations changes a single protein building block (amino acid) in a critical region of the HRAS protein. The most common mutation replaces the amino acid glycine with the amino acid serine at position 12 (written as Gly12Ser or G12S). Costello syndrome is a genetic disorder that affects many parts of the body. ... In biology, mutations are changes to the genetic material (usually DNA or RNA). ... In chemistry, chemistry is really stupid. ... Glycine (Gly, G) is a nonpolar amino acid. ... Serine is one of the 20 natural amino acids. ...


The mutations responsible for Costello syndrome lead to the production of an HRAS protein that is permanently active. Instead of triggering cell growth in response to particular signals from outside the cell, the overactive protein directs cells to grow and divide constantly. This uncontrolled cell division can result in the formation of noncancerous and cancerous tumors. Researchers are uncertain how mutations in the HRAS gene cause the other features of Costello syndrome (such as mental retardation, distinctive facial features, and heart problems), but many of the signs and symptoms probably result from cell overgrowth and abnormal cell division.


Bladder cancer: Some gene mutations are acquired during a person's lifetime and are present only in certain cells. These changes are called somatic mutations and are not inherited. Somatic mutations in the HRAS gene in bladder cells have been associated with bladder cancer. One specific mutation has been identified in a significant percentage of bladder tumors; this mutation substitutes one protein building block (amino acid) for another amino acid in the HRAS protein. Specifically, the mutation replaces the amino acid glycine with the amino acid valine at position 12 (written as Gly12Val or G12V). The altered HRAS protein is permanently activated within the cell. This overactive protein directs the cell to grow and divide in the absence of outside signals, leading to uncontrolled cell division and the formation of a tumor. Mutations in the HRAS gene also have been associated with the progression of bladder cancer and an increased risk of tumor recurrence after treatment. Cystoscopic view of a papillary bladder tumor (top); the bladder wall is visible on the bottom right Bladder cancer refers to any of several types of malignant growths of the urinary bladder. ... Mutations are permanent, sometimes transmissible (if the change is to a germ cell) changes to the genetic material (usually DNA or RNA) of a cell. ... Glycine (Gly, G) is a nonpolar amino acid. ... Valine is one of the 20 natural amino acids, and is coded for in DNA. Nutritionally, valine is also an essential amino acid. ...


Other cancers: Somatic mutations in the HRAS gene are probably involved in the development of several other types of cancer. These mutations lead to an HRAS protein that is always active and can direct cells to grow and divide without control. Recent studies suggest that HRAS mutations may be common in thyroid and kidney cancers. The HRAS protein also may be produced at higher levels (overexpressed) in other types of cancer cells.


  Results from FactBites:
 
HRAS - v-Ha-ras Harvey rat sarcoma viral oncogene homolog - Genetics Home Reference (900 words)
Costello syndrome - caused by mutations in the HRAS gene
Researchers are uncertain how mutations in the HRAS gene cause the other features of Costello syndrome (such as mental retardation, distinctive facial features, and heart problems), but many of the signs and symptoms probably result from cell overgrowth and abnormal cell division.
The HRAS gene is located on the short (p) arm of chromosome 11 at position 15.5.
  More results at FactBites »


 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments
Please enter the 5-letter protection code

Want to know more?
Search encyclopedia, statistics and forums:

 


Lesson Plans | Student Area | Student FAQ | Reviews | Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms.