Phosphorylation polymorphism in the yolk protein 2 of Drosophila hawaiiensis

An intraspecific polymorphism in the electrophoretic migration pattern of the yolk proteins in D. hawaiiensis was established and characterized. The polymorphism includes yolk protein migration patterns of two, three, or four bands by polyacrylamide gel electrophoresis. Peptide mapping analysis demonstrates that in the two band migration pattern YP2 comigrates with YP3, whereas in the three and four band migration patterns YP2 migrates between YP1 and YP3 in addition to comigrating with YP3. It further demonstrates that the top two bands of the four band migration pattern consists of YP1. Phosphatase treatment of the yolk proteins establishes that the different electrophoretic migration patterns of YP2 are caused by different degrees of phosphorylation. It is suggested that the YP1 polymorphism is caused by a yp1 gene modification and that the YP2 polymorphism is caused by two different post-translational processing paths.