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Updated: Aug 29, 2026
High-throughput Screening for Protein-based Inheritance in S. cerevisiae
Published on: August 8, 2017
Restricted changes in major surface protein-2 (msp2) transcription after prolonged in vitro passage of Anaplasma
Diana G Scorpio1, Karen Caspersen, Hiroyuki Ogata
1Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. dscorpio@jhmi.edu
Background:
Anaplasma phagocytophilum strains often vary in Msp2 expression, a situation assumed to be related to immune evasion. However, Msp2 is also an adhesin, and little is known about the role of endogenous msp2 transcriptional changes in the absence of immune selection. Thus, Msp2 profiles and msp2 transcripts of low passage A. phagocytophilum Webster strain, initially comprised of a single abundant msp2 transcript, were re-examined after > or = 20 in vitro passages without immune selection.
Results:
Using an Msp2 monoclonal antibody, immunoblots revealed an unchanged dominant band and several weak bands that appeared with passage. Similarly, msp2 transcript diversity changed, with a decrease in the initially abundant low passage transcript and appearance of a newly abundant and several minor msp2 transcripts with high passage. BLASTN search of the A. phagocytophilum HZ strain genome revealed > or = 52 msp2 paralogs.
Conclusions:
Msp2 expression and msp2 transcription modulate even without immune selective pressures. However, the limited diversity of msp2 transcripts in the absence of immune pressure suggests selection for Msp2 by specific functions beyond that of immune evasion, in spite of a large genomic reservoir for Msp2 diversity.
Insights
Anaplasma phagocytophilum
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial Pathogenesis
Background:
- Anaplasma phagocytophilum strains exhibit variable Msp2 expression, often linked to immune evasion.
- Msp2 also functions as an adhesin, but its role in transcriptional changes without immune pressure is unclear.
- This study investigated Msp2 profiles and transcripts in A. phagocytophilum during in vitro passaging without immune selection.
Purpose of the Study:
- To determine if Msp2 expression and transcription change in Anaplasma phagocytophilum without immune selective pressures.
- To explore the functional implications of Msp2 modulation beyond immune evasion.
Main Methods:
- Immunoblotting using Msp2 monoclonal antibodies to analyze protein profiles.
- Analysis of msp2 transcript diversity using molecular techniques.
- Bioinformatic analysis (BLASTN) of msp2 paralogs in the A. phagocytophilum genome.
Main Results:
- Msp2 protein profiles showed an unchanged dominant band with the appearance of weaker bands over passages.
- Msp2 transcript diversity evolved, with a decrease in the initial transcript and the emergence of new transcripts.
- The A. phagocytophilum genome harbors at least 52 msp2 paralogs.
Conclusions:
- Msp2 expression and transcription are modulated in A. phagocytophilum even without immune selective pressures.
- Limited msp2 transcript diversity suggests Msp2 selection for specific functions beyond immune evasion.
- A large genomic reservoir of msp2 paralogs exists, yet expression remains constrained without immune pressure.
