The MNS Blood Group Antigens, Vr (MNS12) and Mt<sup>a</sup> (MNS14), Each Arise from an Amino Acid Substitution on Glycophorin A
Bibliographic record
Abstract
BACKGROUND AND OBJECTIVES: The antigens, Vr (MNS12) and Mt(a) (MNS14), are low-incidence antigens of the MNS blood group system. The Vr antigen has been found only on the red blood cells (RBCs) of persons of Dutch ancestry whereas the Mt(a) antigen has been found on the RBCs of persons from a wide geographic distribution. The objective of this study was to determine the molecular basis of Vr and Mt(a). MATERIALS AND METHODS: Following RT-PCR amplification of total RNA isolated from one Vr+ person (G488) and one Mt(a+) person (GH), the genes encoding glycophorin A (GYPA) and glycophorin B (GYPB) were cloned and sequenced. To confirm the point mutation observed in the cDNA from G488 (Vr+), GYPA exon 3 was cloned and sequenced from the genomic DNA of G488 and a second unrelated Vr+ person (MU). A restriction fragment length polymorphism (RFLP) assay was used to analyze genomic DNA from 11 Mt(a+) persons (10 unrelated) following PCR amplification of GYPA exon 3. RESULTS: The coding sequence of GYPB was normal in both G488 (Vr+) and GH (Mt(a+)). Sequencing data from GYPA clones derived from G488 showed to full length GYPA sequences: A normal GYPA M allele and a GYPA M allele with a point mutation 197C-->A. Sequencing of GYPA exon 3 from G488 and MU confirmed the point mutation. Sequencing data drom GYPA clones derived from GH showed two full length GYPA sequences: a normal GYPA M allele and a GYPA N allele with a point mutation 230C-->T. RFLP analysis based on the point mutation showed that DNA from 11 Mt(a+) samples were heterozygous for the point mutation. CONCLUSION: The Vr antigen arises from a point mutation 197C-->A on GYPA which is predicted to change serine at position 47 to tyrosine. This change introduces a new alpha-chymotrypsin cleavage site. The Mt(a) antigen arises from a point mutation 230C-->T which is predicted to change threonine at position 58 to isoleucine.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".