Murine ecto-5'-nucleotidase (CD73): cDNA cloning and tissue distribution

Area of Science:

• Molecular Biology
• Immunology
• Biochemistry

Background:

• Ecto-5'-nucleotidase (NT) is a purine catabolic enzyme.
• Understanding NT's tissue-specific distribution and gene regulation is crucial for its functional analysis.

Purpose of the Study:

• To clone the murine cDNA encoding ecto-5'-nucleotidase (NT).
• To investigate the tissue-specific distribution of NT mRNA and enzyme activity.
• To explore NT's role in lymphocyte maturation and the immune system.

Main Methods:

• Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to obtain the murine NT cDNA sequence.
• NT enzyme activity assays were performed on lymphocytes and various tissues.
• RNase protection assays were utilized to determine mRNA levels.

Main Results:

• Murine NT shares high amino acid (94%) and nucleotide (86%) identity with human NT.
• NT enzyme activity was over tenfold higher in mature murine T- and B-lymphocytes compared to immature ones.
• NT activity varied significantly across tissues, with highest levels in placenta, kidney, and forestomach.
• mRNA levels generally correlated with enzyme activity, with notable exceptions in lung and glandular stomach.

Conclusions:

• The cloned murine NT sequence provides a basis for further functional studies.
• Lymphocyte maturation systems are valuable for studying NT gene regulation and immune function.
• The distinct tissue distribution of NT suggests diverse physiological roles.