Gene expressions during the development and sexual differentiation of the olfactory bulb in rats

In this study, expressions of cell-cycle-related genes: p53, retinoblastoma (Rb), p21, bcl-2(alpha), bcl-2(beta); protooncogene c-ski; glial cell mark er protein gene sloop; neurotransmitter gene, substance P and sexual-differ entiation-related genes, androgen receptor (AR) and estrogen receptor beta (ERbeta), are studied in the olfactory bulb of groups of both six female an d six male rats at the ages of 3, 10, 20 and 40 days. Expressions of housek eeping genes such as beta-actin, cyclophilin and proliferating cell nuclear antigens (PCNA) are determined using reverse transcription polymerase chai n reaction (RT-PCR) for the correction of unequal amount of cDNA added into the samples. Using labeled P-dCTP and Phosphorimager technology, relative abundance of radioactivities of the PCR products is obtained by dividing th e radioactivity of each individual sample by the corresponding radioactivit ies of different housekeeping genes. Data evaluated by Two-way ANOVA indica te that only the bcl-2(alpha) gene expression is affected significantly by age, sex and their interactions no matter which of the three housekeeping g enes is used for correction. When beta-actin was used for corrections, effe cts of age but not sex were found in the expressions of p53, Rb, p21, AR, E Rbeta, substance P and sloop genes, but not in bcl-2(beta), c-ski, cyclophi lin and PCNA genes. While cyclophilin was used for corrections, only the p5 3, Rb, AR, ERbeta, substance P and sloop but not the bcl-2(beta), p21, c-sk i, PCNA and beta-actin genes are affected by age. They are all not influenc ed by sex of the animals. Only the AR, ERbeta and S100 beta genes are age-d ependent when PCNA was used for the correction. The other gene expressions are not altered by sex, while the interactions of age and sex were found to be significantly affecting the bcl-2(beta) gene expression. Conclusively, developmental changes of the p53, Rb, AR, ERbeta, substance P and sloop gen es expressions are quite evidenced while only the bcl-2(alpha) gene seems t o change significantly during the sexual differentiation of olfactory bulb in rats. (C) 2000 Elsevier Science B.V. All rights reserved.