About JAK2
The JAK2 gene (Janus Kinase 2) on chromosome 9p24 The V617F mutation in exon 14 is found in>95% of polycythemia vera and ~50% of essential thrombocythemia and primary myelofibrosis. Key targets include Exons 12–24 (JH2 pseudokinase, JH1 kinase) for comprehensive mutation screening.
Mutations: V617F, exon 12 mutations (N542-E543del) | GC content: 50% | Target exons: Exons 12–24 (JH2 pseudokinase, JH1 kinase)
JAK2 Primer Design Challenges
- V617F dominance: Valine 617 in exon 14 is the single most important mutation site, but its high GC context requires optimized amplification
- Exon 12 mutations: N542-E543del and other in-frame indels in the pseudokinase domain require additional amplicon coverage
- Moderate GC (50%): Balanced GC content allows standard PCR, but the JH2 pseudokinase domain (exon 12–14) has localized higher-GC stretches
Recommended Primer Design Parameters for JAK2
| Parameter | Standard Exons | Optimized Regions |
|---|---|---|
| Primer length | 20–22 nt | 22–25 nt |
| GC content | 45–55% | 50–60% |
| Tm | 58–62°C | 60–65°C |
| Amplicon size | 150–300 bp | 180–350 bp |
| Annealing temp | 58–60°C | 60–64°C (touchdown) |
| PCR additive | Standard | Optional 3–5% DMSO for problematic regions |
Key SNPs to Avoid in Primer Binding Sites
When designing JAK2 primers, avoid these clinically significant variants:
- rs77375493 (V617F) — Exon 14 JAK-STAT activating mutation in MPN
- JAK2 exon 12 (N542-E543del) — Exon 12 in-frame deletion in PV
Clinical Validation Required
All JAK2 primers designed with VigyanLLM are for research use only. Clinical diagnostic applications require additional wet-lab validation, Sanger sequencing confirmation, and regulatory approval before patient use.
Recommended Primer Sequences for JAK2 — Engine-Designed on NM_004972
The three pairs below were produced by VigyanLLM's automatic primer design engine directly against the Homo sapiens JAK2 RefSeq mRNA NM_004972 (7023 nt), under the engine's default constraints: 18–25 nt primers, Tm 57–72 °C (optimum 62 °C), GC 40–60%, and an 80–1500 bp amplicon (optimum 150 bp). Every oligo was then re-checked back against the accession — each forward primer matches the sense strand at its stated 1-based position and each reverse primer matches the reverse complement ending at the amplicon's final base (3 of 3 exact matches for this page).
| Pair | Forward (5′→3′) | Reverse (5′→3′) | Tm fwd / rev | GC fwd / rev | Amplicon |
|---|---|---|---|---|---|
| 1 | 5′-TTTGGGAGTGTGGAGATGTG-3′ | 5′-TCATGCTGTAGGGATTTCAGG-3′ | 58.1 / 58.1 °C | 50.0 / 47.6% | 146 bp (nt 3045–3190) |
| 2 | 5′-AAGAAGTAGCACCTCCAGC-3′ | 5′-TCCTTAGGACTGCATCGAAG-3′ | 57.4 / 57.4 °C | 52.6 / 50.0% | 139 bp (nt 1621–1759) |
| 3 | 5′-AGAAAGCAGGTAATCAGACTGG-3′ | 5′-TTTGTCCCACTGAGGTTGTAC-3′ | 58.5 / 58.5 °C | 45.5 / 47.6% | 163 bp (nt 1708–1870) |
Pair 1 leads with a forward/reverse Tm spread of 0.0 °C, no stable hairpin at 37 °C (ΔG ≥ 0.0 kcal·mol−1 on either oligo), self-dimer Tm at most -25.6 °C, no cross-dimer signal, no pair warnings, and a Primer3 pair-quality score of 100.0/100; the suggested starting annealing temperature is 53.1 °C. Pairs 2 and 3 are alternates from the same run — compare their Tm, GC and product columns above against your chemistry (dye-based or probe), then confirm every candidate in silico and on a gel before use.
Specificity: not confirmed.
The engine also launched an automated Primer-BLAST pass (Homo sapiens, RefSeq mRNA), but its report parser returned no expected-amplicon hit — an inconclusive result, not a confirmation. Before ordering, run NCBI Primer-BLAST on each final pair yourself. For genomic-DNA templates this matters even more: an mRNA-based check cannot see processed pseudogenes, repeats or pseudogene-derived off-targets.
How to read this table: these are default whole-transcript designs — they demonstrate what the engine produces under standard constraints and are not positioned over the clinically relevant variants discussed below; to land an amplicon on a specific codon or repeat, design against that region deliberately. Thermodynamics come from Primer3's nearest-neighbor engine (SantaLucia 1998). Example output only: validate each candidate experimentally (gel sizing, efficiency series, melt-curve or probe check) before relying on it.
Design Guidance for JAK2 Assays
JAK2 is a non-receptor tyrosine kinase downstream of cytokine receptors. Its activating variant V617F (c.1849G>T, exon 14) is present in more than 95% of polycythemia vera cases and in a large share of essential thrombocythemia and primary myelofibrosis cases; a separate cluster of insertions and substitutions in exon 12 accounts for most V617F-negative polycythemia vera.
Assay choice follows the question: allele-specific (ARMS-style) PCR gives a rapid answer and an allele burden, hydrolysis-probe discrimination separates homozygotes from heterozygotes directly, and Sanger sequencing of a short exon-14 amplicon remains a valid confirmatory route. In every format the variant should lie inside the amplicon with primer sites in unchanged sequence, and template source matters for low-burden samples — purified granulocyte DNA avoids diluting the mutant allele with lymphocyte DNA. The example pair above (146 bp on NM_004972) does not span codon 617; for V617F work, design across exon 14 and keep the product short.
Before you order: re-check both binding sites against dbSNP and gnomAD — a common variant under one primer causes allele dropout and mysterious assay failures — confirm specificity in silico for the template you will actually use, run an annealing gradient around 53.1 °C (the engine's starting suggestion for pair 1), verify a single band of the expected size on a gel, and record primer sequence, lot and efficiency with the run as MIQE requires.
References
- NCBI Nucleotide — RefSeq NM_004972 (Homo sapiens JAK2 mRNA).
- NCBI Gene — JAK2 (Homo sapiens).
- SantaLucia J Jr. A unified view of polymer, dumbbell, and oligonucleotide DNA nearest-neighbor thermodynamics. Proc Natl Acad Sci USA 1998;95:1460–1465.
- Untergasser A, Cutcutache I, Koressaar T, et al. Primer3—new capabilities and interfaces. Nucleic Acids Res 2012;40:W115–W118.
- Ye J, Coulouris G, Zaretskaya I, et al. Primer-BLAST: a tool to design target-specific primers for polymerase chain reaction. Nucleic Acids Res 2009.
- Bustin SA, Benes V, Garson JA, et al. The MIQE guidelines: minimum information for publication of quantitative real-time PCR experiments. Clin Chem 2009;55:611–622.
Design JAK2 Primers Now
Pre-configured with JAK2-specific parameters. Use our primer design, Tm calculator, and GC content tools for optimal results.