title: Gonadal expression of aromatase and estrogen receptor alpha genes in two races of Tunisian mice and their hypofertile hybrids.
abstract: House mice (Mus musculus domesticus) in Tunisia consists of two races, one carries the 40-acrocentric standard karyotypes and the other one is a robertsonian race (2n=22) homozygous for nine centric fusions (Rb). The F1 hybrids between the two chromosomal races showed a significant decrease in reproductive success and litter size. Such results can be related to the formation of meiotic trivalent in the hybrids leading to the production of viable aneuploid gametes and post-zygotic elimination of embryos due to chromosomal non disjunction events at meiosis. Moreover, testicular histology of F1 and backcross males showed in some cases a breakdown in spermatogenesis. In both females and males, androgens but also estrogens play an important role in gametogenesis. In this study, we have studied aromatase and estrogen receptor alpha (ERalpha) gene expression in the gonads of the two parental races and their chromosomal hybrids. The results showed that aromatase and ERalpha mRNAs are expressed in hybrid males of inter-racial crosses (female22Rb x male40Std and female40Std x male22Rb) and in hybrid females of inter-racial crosses (female22Rb x male40Std) as in the two parental races. However, in hybrid females of inter-racial crosses (female40Std x male22Rb) the amount of aromatase transcripts decreased sharply suggesting that this gene is involved in the breakdown of hybrid fertility in females, but not in males. However, in hybrid males, a putative post-translational modification of this enzyme, in terms of activity, should be verified.
authors.affiliation: Biochemistry Laboratory, University, Caen, France.
authors.forename: Lamia
authors.initials: L
authors.lastname: Saïd
authors.forename: Christelle
authors.initials: C
authors.lastname: Delalande
authors.forename: Janice
authors.initials: J
authors.lastname: Britton-Davidian
authors.forename: Khaled
authors.initials: K
authors.lastname: Saïd
authors.forename: Ali
authors.initials: A
authors.lastname: Saad
authors.forename: Serge
authors.initials: S
authors.lastname: Carreau
mesh_terms: D000818:Animals; D001141:Aromatase / Q000235:genetics*; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D047628:Estrogen Receptor alpha / Q000235:genetics*; D005260:Female; D005786:Gene Expression Regulation; D006824:Hybridization, Genetic; D007621:Karyotyping; D008297:Male; D051379:Mice; D010053:Ovary / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013045:Species Specificity; D013737:Testis / Q000502:physiology; D014416:Tunisia
chemical_list: D047628:Estrogen Receptor alpha; D001141:Aromatase