Expression of Myb^Scer\UAS.cFa under the control of Scer\GAL4^en-e16E or Scer\GAL4^sd-SG29.1 results in malformed wing discs which are overgrown in the area where Myb^Scer\UAS.cFa is overexpressed. Expression of Myb^Scer\UAS.cFa under the control of Scer\GAL4^en-e16E results in an increased number of cells in S phase in the posterior compartment of wing and leg discs compared to controls. Expression of Myb^Scer\UAS.cFa under the control of Scer\GAL4^en-e16E promotes S phase in cells in the zone of non-proliferating cells (ZNC) in the wing disc. No ZNC is detected in wing discs expressing Myb^Scer\UAS.cFa under the control of Scer\GAL4^sd-SG29.1. Expression of Myb^Scer\UAS.cFa under the control of Scer\GAL4^en-e16E or Scer\GAL4^sd-SG29.1 results in a slight increase in apoptosis in the wing disc. Expression of Myb^Scer\UAS.cFa under the control of Scer\GAL4^sd-SG29.1 often results in scalloping of the wing. The overall size of the salivary glands of third instar larvae and of the individual nuclei within the glands is reduced compared to controls in animals expressing Myb^Scer\UAS.cFa under the control of Scer\GAL4^sd-SG29.1. BrdU incorporation is still detected in imaginal ring cells and the endoreplicating nuclei of the salivary glands of larvae expressing Myb^Scer\UAS.cFa under the control of Scer\GAL4^sd-SG29.1 or Scer\GAL4^fkh.PB, as occurs in wild-type larvae.