Differential CRE Expression in Lhrh-cre and GnRH-cre Alleles and the Impact on Fertility in Otx2-Flox Mice.
Neuroendocrinology
; 108(4): 328-342, 2019.
Article
em En
| MEDLINE
| ID: mdl-30739114
ABSTRACT
There is an increasing trend in studies utilizing cell-specific deletion of genes through conditional gene deletion by CRE recombination. Despite numerous advantages, this strategy also has limitations such as ectopic CRE-expression and germline recombination. Two commonly used gonadotropin-releasing hormone (Gnrh)-driven CRE-expressing mice both target GnRH neurons. However, a direct comparison of the cells targeted and their phenotypic outcome have not yet been presented. To compare where recombination takes place, we crossed the Gnrh-cre and Lhrh-cre lines with the Rosa26-LacZ reporter mouse. Lhrh-cre allowed recombination of the Rosa26-LacZ gene in â¼700 cells, which is comparable to the GnRH neuronal population. Surprisingly, there were > 20 times more LacZ expressing cells in the adult Gnrh-creRosa26-LacZ than the Lhrh-creRosa26-LacZ brain. The greatest differences in targeting of the Gnrh-cre and Lhrh-cre lines were found in the septum, the suprachiasmatic nucleus, and the septohypothalamic area. This difference in cells targeted was present from embryonic day 12. A prior study using the Gnrh-cre to delete the transcription factor Otx2 found fewer GnRH neurons, leading to male and female subfertility. To recapitulate this study, we performed a fertility assay in Otx2Lhrh-cre mice. We confirmed the requirement for Otx2 in GnRH neuron development, fertility and correct gonadotropin hormone release in Otx2Lhrh-cre males, but the subfertility was more modest than in Otx2Gnrh-cre and absent in female Otx2Lhrh-cre. This suggests that ectopic expression of Gnrh-cre contributes to the reproductive phenotype observed. Finally, the Cre alleles caused germline recombination of the flox allele when transmitted from either parent, generating embryonic lethal knock-out offspring, producing smaller live litters.
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Base de dados:
MEDLINE
Assunto principal:
Hormônio Liberador de Gonadotropina
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Fatores de Transcrição Otx
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Infertilidade
Limite:
Animals
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article