Related Experiment Videos
Retroviral endogenous transcripts related to the envelope gene of Friend spleen focus-forming virus in normal mouse
Abstract:
Retroviral endogenous sequences related to the envelope (env) gene of Friend spleen focus forming virus (SFFV) and of mink cell focus forming viruses (MCF) are present in the genome of various mouse strains. We have examined the transcription of these SFFV/MCF-related sequences in normal tissues of two mouse strains, ICFW and DBA/2. Cytoplasmic Poly A+ RNAs of normal mouse tissues were analyzed by dot-blot and Northern blot hybridizations with a subcloned env SFFV DNA fragment (0.4 kbp BamH I-Sma I). In both mice, the level of SFFV/MCF env related transcripts was very low in bone marrows and spleens whereas it was high in kidneys. Intermediate levels of transcripts were observed in other tissues (thymus, liver and brain). In both mouse strains, the size of SFFV/MCF env related transcripts varied from one tissue to another. Some transcripts in DBA/2 mice were reminiscent of full-size viral message indicating an occasional expression of xenotropic/MCF endogenous virus in this low-leukemic strain. Sizes of the other SFFV/MCF related env transcripts were unusual, but were similar in both strains for each tissue studied. This last result suggests a tissue-specific transcription of endogenous sequences related to the SFFV/MCF env gene. A 1.8 kb SFFV/MCF env RNA was the major transcript in the tissues which expressed a high level of these env transcripts. Treatment of mice with phenylhydrazine which greatly stimulates erythroid differentiation in spleens increased the level of SFFV/MCF related env RNAs only in the spleens, suggesting a possible correlation between the SFFV/MCF env transcription and the stimulation of the erythroid spleen cells.
Insights
Mouse genomes contain retroviral envelope (env) sequences. Researchers found these sequences transcribe differently across tissues, with high levels in kidneys and low levels in spleens, suggesting tissue-specific gene expression.
Area of Science:
- Molecular Biology
- Virology
- Genomics
Background:
- Mouse genomes harbor endogenous retroviral sequences related to the Friend spleen focus forming virus (SFFV) and mink cell focus forming (MCF) viruses, specifically within the envelope (env) gene.
- The expression patterns and tissue-specific transcription of these SFFV/MCF-related endogenous sequences in normal mice remain incompletely understood.
Purpose of the Study:
- To investigate the transcription of SFFV/MCF-related env sequences in normal tissues of ICFW and DBA/2 mouse strains.
- To determine if the transcription levels and sizes of these endogenous viral transcripts exhibit tissue-specific patterns.
- To explore potential correlations between env gene transcription and erythroid cell stimulation.
Main Methods:
- Analysis of cytoplasmic Poly A+ RNAs from normal mouse tissues using dot-blot and Northern blot hybridizations.
- Utilized a 0.4 kbp SFFV env DNA fragment as a probe for hybridization.
- Examined transcript sizes and levels in various tissues, including bone marrow, spleen, kidney, thymus, liver, and brain.
- Investigated the effect of phenylhydrazine treatment on spleen env RNA levels.
Main Results:
- SFFV/MCF env-related transcripts were detected at low levels in bone marrow and spleen, but at high levels in kidneys of both mouse strains.
- Intermediate transcript levels were observed in the thymus, liver, and brain.
- Transcript sizes varied by tissue, with some in DBA/2 mice resembling full-size viral messages.
- A prominent 1.8 kb SFFV/MCF env RNA was the major transcript in high-expressing tissues.
- Phenylhydrazine treatment significantly increased spleen env RNA levels, correlating with erythroid cell stimulation.
Conclusions:
- Endogenous SFFV/MCF env sequences exhibit tissue-specific transcription patterns in mice.
- The observed transcription patterns suggest a potential role in erythroid cell biology, particularly in the spleen.
- The findings provide insights into the expression of endogenous retroviral elements and their potential functional relevance in normal host tissues.