Human growth hormone DNA sequence and mRNA structure: possible alternative splicing

Area of Science:

• Molecular Biology
• Genetics
• Endocrinology

Background:

• The human growth hormone (hGH) gene structure and its mRNA processing are crucial for understanding growth regulation.
• Previous studies have established the existence of hGH but lacked detailed sequence and splicing information.

Purpose of the Study:

• To determine the complete sequence of the hGH gene.
• To identify the precise location of the mature 5' end of hGH mRNA.
• To investigate the molecular basis for different hGH peptide sizes.

Main Methods:

• Gene sequencing to determine the complete hGH gene sequence.
• Comparison with cloned hGH cDNA to identify intervening sequences.
• S1 mapping to analyze mRNA splicing and identify splice sites.
• Sequence homology analysis to compare hGH mRNA with other hormone genes.

Main Results:

• The complete sequence of the hGH gene was determined.
• Four intervening sequences were identified within the hGH gene.
• Alternate 3' splice sites in one intervening sequence lead to different hGH mRNA isoforms.
• These isoforms generate distinct hGH peptides observed in normal pituitaries.
• An unexpected region of homology was found between the 5' end of hGH mRNA and human glycoprotein hormones.

Conclusions:

• The hGH gene structure, including its intervening sequences and alternative splicing, explains the production of multiple hGH peptide variants.
• The identified sequence homology suggests potential evolutionary or functional links between hGH and glycoprotein hormones, despite their distinct roles.