Editing ABC transporter (section)

==== ABCG ====
Six half transporters with ATP binding sites on the N terminus and trans-membrane domains at the C terminus make up the ABCG subfamily.  This orientation is opposite of all other ABC genes. There are only 5 ABCG genes in the human genome, but there are 15 in the Drosophila genome and 10 in yeast.  
The ABCG2 gene was discovered in cell lines selected for high level resistance for [[mitoxantrone]] and no expression of [[ABCB1]] or [[ABCC1]]. [[ABCG2]] can export [[anthracycline]] anticancer drugs, as well as [[topotecan]], [[mitoxantrone]], or [[doxorubicin]] as substrates. [[Chromosomal translocations]] have been found to cause the ABCG2 amplification or rearrangement found in resistant cell lines.<ref name="Dean_2001"/>