Expression and potential function of the c-mos proto-oncogene in human eggs

Abstract

To investigate the expression and possible function of the c-mos proto-oncogene in human eggs. Eggs obtained as discarded material from assisted reproductive technology procedures were analyzed for c-mos messenger RNA by reverse transcriptase-polymerase chain reaction. As an approach to investigating c-mos function, we measured maturation-promoting factor (MPF) activity (histone H1 kinase) in eggs without and with inhibition of protein synthesis. Detection of RNA transcripts of c-raf was included as control. Transcripts of c-mos were detected in small fractions of individual eggs, indicating that c-mos is abundantly transcribed. Inhibition of protein synthesis resulted in loss of MPF, leading to chromatin decondensation and reformation of a nucleus. C-raf maternal messages were also detectable in individual human eggs. The c-mos proto-oncogene is an abundant maternal message in human eggs as in other species. The effects of inhibiting protein synthesis in human eggs are similar to those obtained in mouse and Xenopus eggs, either as a consequence of protein synthesis inhibition or specific ablation of c-mos RNA by injection of anti-sense oligonucleotides. The c-mos gene product is thus likely to play a critical role in human oocyte meiosis by regulating the activity of MPF.