Human follicle-stimulating hormone beta-subunit gene encodes multiple messenger ribonucleic acids

Area of Science:

• Molecular Biology
• Genetics
• Endocrinology

Background:

• Follicle-Stimulating Hormone (FSH) is a crucial pituitary gonadotropin.
• FSH is synthesized from separate alpha- and beta-subunit genes.
• Understanding the human FSH beta gene structure is key to comprehending FSH regulation.

Purpose of the Study:

• To isolate and characterize the complete human FSH beta gene.
• To elucidate the transcriptional unit and regulatory elements of the FSH beta gene.
• To investigate the mechanisms of mRNA processing for FSH beta.

Main Methods:

• Isolation of a 12 kb DNA fragment containing the human FSH beta gene from a genomic DNA library.
• Nucleotide sequencing of the FSH beta gene.
• Southern blot analysis of human genomic DNA.
• Analysis of transcriptional unit, introns, exons, and polyadenylation sites.

Main Results:

• The human FSH beta gene spans 3.9 kb and contains two introns.
• Alternative splicing of the first exon generates two 5'-untranslated regions (Exon IA and IB).
• Two distinct polyadenylation sites are utilized, with one leading to a long 3'-untranslated sequence.
• At least four distinct FSH beta mRNA species are processed from a single gene, all encoding identical peptides.
• Similar mRNA distributions were observed in normal pituitary tissue and pituitary adenomas.

Conclusions:

• The human FSH beta gene exhibits complex mRNA processing through alternative splicing and polyadenylation.
• Despite transcript diversity, all processed mRNAs encode identical FSH beta peptides.
• These findings provide insights into the molecular basis of FSH production and regulation.