Human lysosomal acid phosphatase: cloning, expression and chromosomal assignment.

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• Lysosomal acid phosphatase (LAP) is a crucial enzyme involved in cellular degradation.
• Understanding the genetic and molecular basis of LAP is essential for comprehending lysosomal storage disorders.

Purpose of the Study:

• To isolate and characterize the cDNA clone encoding human lysosomal acid phosphatase.
• To determine the gene's chromosomal localization and analyze the deduced protein sequence.
• To investigate the functional expression of human LAP.

Main Methods:

• Isolation of a human placenta cDNA library using lambda gt11.
• Hybridization of cDNA with mRNA from human liver and HL-60 cells.
• Gene localization using chromosome analysis.
• DNA sequencing and amino acid sequence analysis.
• Expression of cDNA in monkey COS cells via the pSVL vector.

Main Results:

• A 2112-bp cDNA clone (lambda CT29) for human LAP was isolated.
• The LAP gene was localized to human chromosome 11.
• The deduced amino acid sequence indicated a signal sequence, potential glycosylation sites, and a transmembrane domain.
• A 60% homology was observed with human prostatic acid phosphatase N-terminal sequences.
• Transfected monkey COS cells expressed enzymatically active LAP.

Conclusions:

• The study successfully isolated and characterized the human LAP cDNA, providing insights into its structure and function.
• The findings suggest a potential evolutionary relationship between lysosomal and prostatic acid phosphatases.
• The expression of active LAP in COS cells validates the cDNA's integrity and functional potential.