RNA-directed DNA polymerase from particles released by normal goose cells

Area of Science:

• Molecular Biology
• Virology
• Cell Biology

Background:

• Avian retroviruses and related viruses utilize RNA-directed DNA polymerase for replication.
• Understanding the origin and nature of such enzymes in different avian species is crucial for virological research.

Purpose of the Study:

• To investigate the presence and characteristics of RNA-directed DNA polymerase and associated enzymes in goose embryo cells.
• To determine the relationship of these enzymatic activities to known avian viruses.

Main Methods:

• Culturing goose embryo cells and extracting associated particles.
• Assaying for RNA-directed DNA polymerase and RNase H activities, requiring Nonidet P-40.
• Characterizing the DNA polymerase by size and inhibition with specific antibodies.
• Analyzing cellular DNA for reticuloendotheliosis virus-related nucleotide sequences.

Main Results:

• Goose embryo cells released particles with detectable RNA-directed DNA polymerase and RNase H activities upon Nonidet P-40 treatment.
• These particles were non-infectious and did not exhibit endogenous DNA synthesis.
• The goose particle DNA polymerase shared size similarities with spleen necrosis virus DNA polymerase and was inhibited by specific immunoglobulin G.
• No reticuloendotheliosis virus-related nucleotide sequences were found in the DNA of goose cells producing these particles.

Conclusions:

• Goose embryo cells produce unique particles containing RNA-directed DNA polymerase and RNase H activities.
• The enzymatic properties suggest a relationship to spleen necrosis virus, but the absence of viral sequences indicates a non-reticuloendotheliosis virus origin.
• These findings contribute to understanding non-reticuloendotheliosis avian retroviral elements.