Dominant Defects in Drosophila Eye Pigmentation Resulting From a Euchromatin-Heterochromatin Fusion Gene

摘要: We have isolated a dominant mutation, pugilistDominant (pugD), that causes variegated reductions in pteridine and ommochrome pigmentation of the Drosophila eye. The effect pugD on is most dramatic: only remaining pigment consists thin ring around periphery eye with few scattered spots center. mutation disrupts gene encodes homolog trifunctional enzyme methylenetetrahydrofolate dehydrogenase (MTHFD; E.C.1.5.1.5, E.C.3.5. 4.9, E.C.6.3.4.3). This produces cofactor utilized purine biosynthesis. Because pteridines are derived from GTP, defect may result an impairment production purines. mutant allele portion MTHFD coding region fused to approximately 1 kb highly repetitive DNA. Transcription translation both parts required for phenotype. DNA 140 nearly perfect repeats sequence AGAGAGA, significant component centric heterochromatin. unusual nature protein produced by this be responsible its dominance. also account aspect It promote occasional association locus heterochromatin, accompanied inactivation pugD, manner similar proposed mode action brownDominant.