Human alpha 2-HS-glycoprotein: the A and B chains with a connecting sequence are encoded by a single mRNA transcript

Area of Science:

• Biochemistry
• Genetics
• Molecular Biology

Background:

• Alpha 2-HS-glycoprotein (AHSG) is a plasma protein with known roles in bone mineralization and immune response.
• AHSG consists of two subunits, A and B chains.

Purpose of the Study:

• To isolate and characterize the human cDNA for AHSG.
• To determine the genetic basis and expression of AHSG.

Main Methods:

• Screening of an adult human liver cDNA library using a mixed oligonucleotide probe.
• Sequencing of isolated AHSG cDNA clones.
• Gene mapping of AHSG to human chromosome 3.

Main Results:

• Isolation of cDNA clones containing the entire AHSG coding sequence (approx. 1.5 kb).
• Demonstration that A and B chains are encoded by a single mRNA transcript.
• Identification of a novel 40-amino-acid connecting sequence between A and B chains, potentially involved in post-translational processing.
• Mapping of the AHSG gene to chromosome 3q21----qter.

Conclusions:

• The AHSG cDNA sequence provides a complete coding sequence, including a novel connecting peptide.
• The findings suggest AHSG is synthesized from a single mRNA transcript with potential alternative processing.
• The AHSG gene is located on human chromosome 3, facilitating further genetic studies.