GATA2

GATA2 or GATA-binding factor 2 is a

Inactivating mutations of the GATA2 gene cause a reduction in the cellular levels of GATA2 and the development of a wide range of familial hematological, immunological, lymphatic, and/or other disorders that are grouped together into a common disease termed GATA2 deficiency. Less commonly, these disorders are associated with non-familial (i.e. sporadic or acquired) GATA inactivating mutations. GATA2 deficiency often begins with seemingly benign abnormalities but if untreated progresses to life-threatening opportunistic infections, virus-induced cancers, lung failure, the myelodysplastic syndrome (i.e. MDS), and/or acute myeloid leukemia, principally acute myeloid leukemia (AML), less commonly chronic myelomonocytic leukemia (CMML), and rarely a lymphoid leukemia.^[6][7]

Overexpression of the GATA2 transcription factor that is not due to mutations in the GATA2 gene appears to be a secondary factor that promotes the aggressiveness of non-familial EVI1 positive AML as well as the progression of prostate cancer.^{[8][9][10][11]}

GATA2 gene

The GATA2 gene is a member of the evolutionarily conserved

Scores of different types of inactivating GATA mutations have been associated with GATA2 deficiency; these include frameshift, point, insertion, splice site and deletion mutations scattered throughout the gene but concentrated in the region encoding the GATA2 transcription factor's C-ZnF, N-ZnF, and 9.5 kb sites. Rare cases of GATA2 deficiency involve large mutational deletions that include the 3q21.3 locus plus contiguous adjacent genes; these mutations seem more likely than other types of GATA mutations to cause increased susceptibilities to viral infections, developmental lymphatic disorders, and neurological disturbances.^[6][17]

One GATA2 mutation is a gain of function type, i.e. it is associated with an increase in the activity rather than levels of GATA2. This mutation substitutes valine for leucine in the 359 amino acid position (i.e. within the N-ZnF site) of the transcription factor and has been detected in individuals undergoing the blast crisis of chronic myelogenous leukemia.^[9][20]

Pathological inhibition

Analyses of individuals with AML have discovered many cases of GATA2 deficiency in which one parental GATA2 gene was not mutated but silenced by hypermethylation of its gene promoter. Further studies are required to integrate this hypermethylation-induced form of GATA2 deficiency into the diagnostic category of GATA2 deficiency.^[19]

Pathological stimulation

Non-mutational stimulation of GATA2 expression and consequential aggressiveness in EVI1-positive AML appears due to the ability of

GATA2 binds to a specific nucleic acid sequence viz., (T/A(GATA)A/G), on the promoter and enhancer sites of its target genes and in doing so either stimulates or suppresses the expression of these target genes. However, there are thousands of sites in human DNA with this nucleotide sequence but for unknown reasons GATA2 binds to <1% of these. Furthermore, all members of the GATA transcription factor family bind to this same nucleotide sequence and in doing so may in certain instances serve to interfere with GATA2 binding or even displace the GATA2 that is already bound to these sites. For example, displacement of GATA2 bond to this sequence by the GATA1 transcription factor appears important for the normal development of some types of hematological stem cells. This displacement phenomenon is termed the "GATA switch". In all events, the actions of GATA2, particularly with referenced to its interactions with many other gene-regulating factors, in controlling its target genes is extremely complex and not fully understood.^{[6][14][15][16]}

GATA2-related disorders

Inactivating GATA2 mutations

Familial and sporadic inactivating mutations in one of the two parental GATA2 genes causes a reduction, i.e. a haploinsufficiency, in the cellular levels of the GATA2 transcription factor. In consequence, individuals commonly develop a disease termed GATA2 deficiency. GATA2 deficiency is a grouping of various clinical presentations in which GATA2 haploinsufficiency results in the development over time of hematological, immunological, lymphatic, and/or other presentations that may begin as apparently benign abnormalities but commonly progress to life-threatening opportunistic infections, virus infection-induced cancers, the myelodysplastic syndrome, and/or leukemias, particularly AML.^[6][7] The various presentations of GATA2 deficiency include all cases of Monocytopenia and Mycobacterium Avium Complex/Dendritic Cell Monocyte, B and NK Lymphocyte deficiency (i.e. MonoMAC) and the Emberger syndrome as well as a significant percentage of cases of familial myelodysplastic syndrome/acute myeloid leukemia, congenital neutropenia, chronic myelomonocytic leukemia, aplastic anemia, and several other presentations.^{[6][7][29][30]}

Activating GATA2 mutation

The L359V gain of function mutation (see above section on mutation) increases the activity of the GATA2 transcription factor. The mutation occurs during the blast crisis of chronic myelogenous leukemia and is proposed to play a role in the transformation of the chronic and/or accelerated phases of this disease to its blast crisis phase.^[9][20]

Repression of GATA2

The repression of GATA2 expression due to

See also

• GATA transcription factor
• GATA2 deficiency
• MonoMAC
• Emberger syndrome

References