Genetic diversity of two evergreen oaks (Quercus suber L. and Q (ilex) rotundif...

• Author(s): Coelho, A. C. ; Lima, M. B. ; Neves, D. ; Cravador, A.
• Date: 2006
• Persistent ID: http://hdl.handle.net/10400.1/1223
• Origin: Sapientia - Universidade do Algarve
• Subject(s): AFLP; Genetic diversity; Genetic introgression; Quercus suber (L.); Quercus ilex subsp. rotundifolia (Lam.)
• Document Type: Article
• Language: English

Description

Expression of POU1F1 gene, a member of the POU homeodomain family of transcription factors, is necessary for normal differentiation, development and survival of three anterior pituitary cell types (thyrotrophs, somatotrophs and lactotrophs) and for the proper expression of growth hormone (GH ), prolactin (PRL), thyroid-stimulating hormone (TSH ) genes and POU1F1 gene itself. Alternative splicing forms of this gene have been reported in different species, with few functional studies. Apart from the POU1F1-Wild-type with the expected length, in this work we isolated three additional splicing variants: POU1F1-β, with a 78 bp insert in the trans-activation domain; POU1F1-γ that lacks exon 3 and POU1F1-δ that lacks exons 3, 4 and 5. Four different protein isoforms were also detected by Western blot in the sheep pituitary tissue. Functional assays were performed to study the trans-activation of GH and PRL promoters by the splicing variants. Regarding the PRL promoter, the β variant presented only 12% of the Wild-type trans-activation capacity. Variants γ and δ showed no capacity to trans-activate PRL promoter. Both γ and δ variants acted as repressors of Wt, reducing significantly the trans-activation made by Wt alone ( p<0.05). Concerning the GH promoter, the β variant presented a trans-activation capacity 10% higher than Wt. Wt and β variants strongly interact in the activation of GH promoter doubling the trans-activation potential of Wt. Variants γ and δ showed no capacity to trans-activate the GH promoter and both acted as repressors, reducing significantly ( p<0.001) the trans-activation performed by Wt. This work presents, for the first time, the characterization of four splicing forms of Ovis aries POU1F1 gene.