Disease relevance of FST

• RCAS retroviruses were used to overexpress in the chick retina in ovo either follistatin (FS), an activin-binding protein and inhibitor, or alkaline phosphatase (AP), as control [1].

High impact information on FST

• One site that is located between the seventh and eight follistatin-like domain includes 3 closely spaced serine-glycine (SG) consensus sequences and carries exclusively heparan sulfate side chains [2].
• Effects of follistatin overexpression on cell differentiation in the chick embryo retina [1].
• Increases in cell death were also observed in FS-treated retinas [1].
• FS-treated retinas appeared normal until ED 8, when they showed a reduction of the inner plexiform layer, accompanied by a marked decrease in the frequency of amacrine cells [1].
• Here, we report that during chick limb development Follistatin enhances BMP-7 action to induce muscle growth but prevents the ability of BMP-7 to induce apoptosis and muscle loss [3].

Biological context of FST

• The function of this protein during embryogenesis in higher vertebrates is unclear, and to further our understanding of its role we have cloned, sequenced, and performed an in-depth expressional analysis of the chick homologue of follistatin [4].
• When tested in dissociated retinal cultures, activin did not appear to affect cell survival or proliferation, but it exerted marked inhibitory effects on the differentiation of photoreceptors, while stimulating the differentiation of nonphotoreceptor neurons; both effects were concentration-dependent and follistatin-sensitive [5].
• We also give revised data for early neurectodermal expression of chick follistatin (Connolly et al., 1995, Developmental Genetics 17(1), 65-77) and follow the new ectopic expression of both genes during the induction of a second neural axis, after grafting of Hensen's node into a peripheral position in a host blastoderm [6].
• Expression of the mRNA for the activin/inhibin binding protein, follistatin, was detected in theca and granulosa samples with the greatest expression found in small yellow follicle samples for both cell layers [7].
• Myostatin, follistatin and activin-B cDNAs were synthesized by reverse-transcription polymerase chain reaction (RT-PCR) [8].

Anatomical context of FST

• Follistatin was first detected in Hensen's node and subsequently in the region described by Spratt [1952] as the neuralising area [4].
• We also present evidence that follistatin may have a later role in the resegmentation of the somites [4].
• Follicle-stimulating hormone regulation of inhibin alpha- and beta(B)-subunit and follistatin messenger ribonucleic acid in cultured avian granulosa cells [9].
• This represents the first report, to our knowledge, of the detection of follistatin mRNA in the hen ovary and rooster testes [10].
• Ovarian follicle development in the laying hen is accompanied by divergent changes in inhibin A, inhibin B, activin A and follistatin production in granulosa and theca layers [11].

Associations of FST with chemical compounds

• Follistatin, a secreted glycoprotein, has been shown to act as a potent neural inducer during early amphibian development [4].
• The ORF encodes a secreted protein of approx 38 kDa, containing a single cysteine-rich domain that shows a strong relationship with the second of the four from which Follistatin is constructed [6].
• The role of long range, local and direct signalling molecules during chick feather bud development involving the BMPs, follistatin and the Eph receptor tyrosine kinase Eph-A4 [12].
• Estradiol regulation of follistatin and inhibin alpha- and beta(B)-subunit mRNA in avian granulosa cells [13].
• This discussion includes follicle-stimulating hormone, luteinizing hormone, inhibin, activin, follistatin, tumor necrosis factor-alpha, growth factors such as transforming growth factor-beta, interleukins, and interferon [14].

Other interactions of FST

• In addition we also describe the expression pattern of activin beta A and activin beta B, proteins that have previously been shown to be able to interact with follistatin [4].
• Immunocytochemistry and in situ hybridization have shown that activin/inhibin subunits alpha, betaA, and betaB; receptors II and IIB; follistatin; and a follistatin-like gene are expressed in different regions of the chick embryo retina in developmentally regulated patterns [5].
• No myostatin, activin-B, follistatin or bFGF expression was detected in either cell culture at 0 h [15].
• Expression of four BMP antagonist genes, noggin, chordin, gremlin and Follistatin, was examined during chick feather development [16].

Analytical, diagnostic and therapeutic context of FST

• Northern blot analysis was performed, and a follistatin mRNA transcript of approximately 2 [10].
• Levels of mRNA for inhibin/activin betaA and betaB subunits, inhibin alpha subunit, follistatin and ActRIIB mRNA in pituitary were undetectable by quantitative PCR (<2 amol/reaction) [17].

References