Induction of hyaluronan synthase 2 by XXXX chorionic gonadotropin in mural granulosa cells of @entity1641 preovulatory follicles.

@entity1 @entity70994 @entity1641 @entity1465 @entity19
In contrast to other species, the preovulatory rise in gonadotropins in mares causes a remarkable expansion of the entire granulosa cell layer in vivo, suggesting that hyaluronan (HA) synthesis may be regulated in mural granulosa cells in this species. The objectives of this study were to clone and characterize @entity1641 @entity70994 ( @entity70994 ) and investigate the regulation of its transcript and of HA synthesis in @entity1641 follicles during @entity1 chorionic gonadotropin ( @entity1465 )- induced ovulation. Results showed that the @entity1641 @entity70994 cDNA contains a 5'-untranslated region of 436 bp, an open reading frame of 1659 bp, and a 3'-untranslated region of 707 bp. The open reading frame encodes a 552-amino acid protein that is highly conserved (98-99% identity), compared with other known @entity1 homologs. The regulation of @entity70994 mRNA was studied in @entity1641 follicles isolated during estrus between 0 and 39 h after an ovulatory dose of @entity1465 and in corpora lutea obtained on d 8 of the estrous cycle. Results from semiquantitative RT-PCR/Southern blotting analyses revealed a transient induction of @entity70994 during the ovulatory process. Levels of @entity70994 transcripts were undetectable in follicles before @entity1465 treatment (0 h), increased markedly after gonadotropin treatment (P < 0.05), but returned to undetectable levels in corpora lutea. Analyses performed on isolated preparations of theca interna and granulosa cells showed that the granulosa cell layer was the predominant site of @entity70994 expression. An immunohistochemical approach showed that this induction of @entity70994 transcript was accompanied by a dramatic increase in HA production after @entity1465 treatment. The isolation and characterization of a 1.8-kb fragment of genomic sequence located immediately upstream of @entity1641 @entity70994 , and comparison with corresponding @entity1 and @entity19 genomic regions identified several conserved putative cis-acting elements. Thus, this study describes the primary structure of @entity1641 @entity70994 , demonstrates for the first time the regulation of @entity70994 in mural granulosa cells during the ovulatory process in vivo and identifies a valuable model in which to study the molecular control of @entity70994 gene expression.
