Transcription of four satellite DNA subfamilies in Diprion pini (Hymenoptera, Symphyta, Diprionidae).

Four satellite DNA subfamilies Ps, Pv, Pv65 and Ec, resulting from the evolution of a common ancestral motif, were isolated and characterized in the genomic DNA of Diprion pini, a phytophagous of Pinus sylvestris. Consensus sequences were 148-312 bp long. Sequence analyses revealed that these satellite subfamilies have evolved from a 45-bp ancestral motif. The amounts of each satellite in the genome (0 - 10%) and the accessibility of the DNA to restriction enzymes were sex dependent. The migration of each monomer in polyacrylamide gels and the electrophoretic migration of d(AT) n > or = 3 residues showed that all four satellite subfamilies are curved. Their transcription was analyzed using reverse transcription and the polymerase chain reaction. Three satellite DNA subfamilies were transcribed on both strands, and in both sexes. However, the female satellite DNAs seem to be more actively transcribed than those of males, indicating that transcription is not constitutive. The lack of any significant open reading frame in satellite monomers indicates that the RNA may function as structural or catalytic RNA rather than encoding protein.