Cloning, sequencing and expression of cDNA encoding an insect V-ATPase subunit E

Area of Science:

• Molecular Biology
• Biochemistry
• Insect Physiology

Background:

• Vacuolar-type proton ATPases (V-ATPases) are essential proton pumps found in all eukaryotes.
• Subunit E is a critical component of the V-ATPase, but its invertebrate sequences were previously uncharacterized.
• Understanding V-ATPase diversity across species provides insights into cellular functions and evolution.

Purpose of the Study:

• To clone and characterize the first invertebrate cDNA sequence encoding V-ATPase subunit E.
• To investigate the evolutionary relationship of insect V-ATPase subunit E with its mammalian and yeast counterparts.
• To determine the gene copy number for insect V-ATPase subunit E.

Main Methods:

• Immuno-shot-gun screening of a Manduca sexta posterior larval midgut cDNA library.
• Amino acid sequence analysis and comparison with known V-ATPase subunit E sequences.
• Southern and Northern blot analyses to assess gene and transcript abundance.

Main Results:

• The first invertebrate cDNA sequence for V-ATPase subunit E was successfully cloned from Manduca sexta.
• The deduced amino acid sequence exhibited 64% identity to mammalian V-ATPase E-subunit and 34% to yeast.
• Southern and Northern blot results indicated the presence of a single gene encoding this insect subunit E.

Conclusions:

• This study provides the foundational invertebrate V-ATPase subunit E sequence, expanding the known diversity of this essential enzyme.
• The high sequence identity to mammalian and yeast homologs suggests conserved functional roles.
• The single-gene finding implies a conserved regulatory mechanism for V-ATPase subunit E in insects.