ARF GTPase-activating protein GIT2 is an enzyme

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 that in humans is encoded by the GIT2 gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

.

Model organisms

Model organism

Model organism

A model organism is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the organism model will provide insight into the workings of other organisms. Model organisms are in vivo models and are widely used to...

s have been used in the study of GIT2 function. A conditional knockout mouse

Knockout mouse

A knockout mouse is a genetically engineered mouse in which researchers have inactivated, or "knocked out," an existing gene by replacing it or disrupting it with an artificial piece of DNA...

 line, called Git2^Gt(XG510)Byg was generated as part of the International Knockout Mouse Consortium

International Knockout Mouse Consortium

The International Knockout Mouse Consortium is a scientific endeavour to produce a collection of mouse embryonic stem cell lines that together lack every gene in the genome, and then to distribute the cells to scientific researchers to create knockout mice to study...

 program — a high-throughput mutagenesis project to generate and distribute animal models of disease to interested scientists — at the Wellcome Trust Sanger Institute.

Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion.

Git2 knockout mouse phenotype

Characteristic	Phenotype
Homozygote viability	Normal
Fertility	Normal
Body weight	Normal
Anxiety Open Field (animal test) The Open Field Test is an experiment used to assay general locomotor activity levels and anxiety in rodents in scientific research.- Experimental Design :...	Normal
Neurological assessment	Normal
Grip strength	Normal
Hot plate Hot plate test The hot plate test is a test of the pain response in animals. It is used in basic pain research and in testing the effectiveness of analgesics by observing the reaction to pain caused by heat. It was proposed by Eddy and Leimbach in 1953....	Abnormal
Dysmorphology	Normal
Indirect calorimetry	Normal
Glucose tolerance test Glucose tolerance test A glucose tolerance test is a medical test in which glucose is given and blood samples taken afterward to determine how quickly it is cleared from the blood. The test is usually used to test for diabetes, insulin resistance, and sometimes reactive hypoglycemia and acromegaly, or rarer disorders of...	Normal
Auditory brainstem response Auditory Brainstem Response The auditory brainstem response is an auditory evoked potential extracted from ongoing electrical activity in the brain and recorded via electrodes placed on the scalp. The resulting recording is a series of vertex positive waves of which I through V are evaluated...	Normal
DEXA	Normal
Radiography Radiography Radiography is the use of X-rays to view a non-uniformly composed material such as the human body. By using the physical properties of the ray an image can be developed which displays areas of different density and composition....	Normal
Body temperature	Normal
Eye morphology	Normal
Clinical chemistry	Abnormal
Haematology	Abnormal
Peripheral blood lymphocytes	Normal
Micronucleus test Micronucleus test A micronucleus test is a test used in toxicological screening for potential genotoxic compounds. There are two major versions of this test, one in vivo and the other In vitro. The in vivo test normally uses mouse bone marrow or mouse peripheral blood. Micronuclei were first used to quantify...	Normal
Heart weight	Normal
Tail epidermis wholemount	Normal
Skin Histopathology	Normal
Brain histopathology	Abnormal
All tests and analysis from

Mice lacking Git2 had no significant defects in viability or fertility

Fertility

Fertility is the natural capability of producing offsprings. As a measure, "fertility rate" is the number of children born per couple, person or population. Fertility differs from fecundity, which is defined as the potential for reproduction...

, so further tests were carried out and four significant phenotypes were reported:

• Mutant
  Mutant
  In biology and especially genetics, a mutant is an individual, organism, or new genetic character, arising or resulting from an instance of mutation, which is a base-pair sequence change within the DNA of a gene or chromosome of an organism resulting in the creation of a new character or trait not...
  
   mice had differences in their clinical blood chemistry compared to wildtype control mice.
• Mutant male mice had a decrease in white blood cell count.
• An increased thickness in hippocampus
  Hippocampus
  The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
  
   was observed.
• Mutant female mice were slower to respond to heat when placed on a hotplate.

Further reading