Bonilla E, Mazo J

Language: Spanish
References: 14
Page: 40-44
PDF size: 95.94 Kb.

ABSTRACT

Ethylnitrosourea (ENU), an alkylating agent, induces congenital anomalies in fetuses when it is administered to pregnant animals. It has been reported that ENU induced apoptosis and growth arrest in fetal tissues and organs immediately after its administration to pregnant rats. The mutagenic properties of ENU are well documented, but less is known about its effects on transcription. In the present study we have evaluated the effect of ENU on the viability and gene expression in fetal oocytes cultured in vitro. Results show that oocyte survival decreased significantly to 70% after 24 h exposure to 1 mM ENU. mRNA from control oocytes and oocytes exposed to 1mM ENU was reverse transcribed. Then, the 3’ end of first-strand cDNA was elongated with deoxyadenosine residues, and cDNA was PCR amplified. In average, the amount of cDNA generated from 10 ENU oocytes was five times lower than that generated from the same number of control oocytes. Differential screenings were performed to monitor altered expression of genes in ENU exposed oocytes. Confirmation of the identity of clones corresponding to deregulated genes was obtained by Southern blot. After screening 6,000 clones, only one was found to be clearly down regulated in oocytes exposed to ENU: the 7.6-kDa subunit of RNA polymerase II. We conclude that ENU diminishes RNA expression levels in oocytes exposed to this agent, probably due to down-regulation of the 7.6-kDa subunit of RNA polymerase II.

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