Molecular cloning of cDNA for equine follistatin and its gene expression in the reproductive tissues of the mare.

The article presents the successful molecular cloning of the cDNA for the equine follistatin from an ovarian clone library and studies its gene expression in the mare’s reproductive tissues. The results imply that follistatin may play a significant role in maintaining pregnancy in mares.

Molecular Cloning Method and Findings

• Equine follistatin was cloned using an equine ovarian cDNA library, made up of 1.2 x 10⁵ independent clones.
• A solitary positive clone named EQ-FS-1 was isolated for this purpose. The clone’s cDNA sequence was then determined.
• EQ-FS-1 had a complete open reading frame encoded with 344 amino acid residues. These amino acids’ sequence was more than 95% similar to other mammalian species.

Follistatin Expression in Multiple Tissues

• The researchers used Northern blot analysis to check for the levels of follistatin mRNA in equine reproductive tissues like uteroplacental tissues, follicles and corpora lutea.
• They found the follistatin mRNA levels varied amongst the different tissues, but it was present in all the examined areas.

Follistatin Expression in Granulosa Cells

• On taking a closer look at the individual cells in an equine follicle, the expression of follistatin mRNA was found to be limited to granulosa cells only.

Follistatin Expression During Pregnancy

• The research also identified changes in the level of follistatin expression in uteroplacental tissues during pregnancy. It found that the follistatin expression levels decreased after mid-pregnancy.
• This pattern of decrease during pregnancy suggests that follistatin might be involved in maintaining pregnancy. However, this is an inference, and further research would be required to confirm this.