Published: June 03, 2026, 05:49 UTC
CRISPR-Cas9 has dominated the field of functional genomics for a decade. It is the tool of choice for perturb-seq — the powerful technique that combines CRISPR-mediated gene disruption with single-cell RNA sequencing to read out the effects of genetic perturbations across thousands of cells at once. Cas9’s simplicity and efficiency have made it the default, and for good reason.
But it is not the only CRISPR system. Cas12a (formerly known as Cpf1), an enzyme discovered in 2015, has unique properties that Cas9 lacks: it can process its own CRISPR array from a single transcript, enabling highly multiplexed targeting with a single construct. This ability has been tantalizing for perturb-seq applications, but a fundamental technical barrier has prevented its adoption. Cas12a’s self-processing activity makes it difficult to assign individual guide RNAs to individual cells — a requirement for single-cell readout.
A new paper in Nature Communications from researchers led by Snetkova, Galan, Lopez, and colleagues breaks through that barrier. The team has engineered a tunable Cas12a platform that not only solves the guide-assignment problem but adds something Cas9-based systems cannot easily offer: chemically reversible, temporal control of gene repression.
The Cas12a Advantage
Cas9 works with a single guide RNA (sgRNA) that must be expressed separately for each target gene. Multiplexing — targeting multiple genes at once — requires expressing multiple sgRNAs from separate promoters, which is bulky and inefficient.
Cas12a processes its own guide RNA array. A single transcript encoding multiple CRISPR RNAs (crRNAs) is cleaved by the Cas12a enzyme itself into individual guides, each ready to direct the nuclease to its target. This means a single construct can simultaneously target many genes. For perturb-seq — where each cell ideally receives one perturbation and the goal is to screen hundreds or thousands of genes in parallel — Cas12a’s natural multiplexing could be transformative. But the very self-processing activity that enables multiplexing also destroys the linkage between the guide sequence and the cell’s barcode, making it impossible to know which perturbation a given cell received.
The new platform solves this by redesigning the pre-crRNA expression vectors so that individual guides can be accurately detected and assigned at the single-cell level — preserving Cas12a’s multiplexing capability while recovering the crucial guide-to-cell linkage.
Tunable and Reversible
The paper’s second major innovation is chemically tunable control. The team fused catalytically dead Cas12a (dCas12a) to an auxin-inducible degron — a protein domain that triggers rapid degradation of the entire fusion protein when the plant hormone auxin (indole-3-acetic acid, IAA) is added to the culture medium. Remove the auxin, and dCas12a levels recover.
This creates a system in which gene repression via CRISPRi (CRISPR interference, where dCas12a fused to a KRAB repressor silences gene transcription) can be turned on, off, and back on again with simple chemical addition or removal — a temporal precision that constitutive dCas9-KRAB systems cannot match.
The degron system enables a fundamentally new class of experiments. Researchers can:
- Repress a gene, observe the immediate phenotypic consequences
- Wash out the inducer, watch the gene’s expression recover
- Observe whether the phenotype reverses — distinguishing acute requirements from compensatory adaptations
This temporal resolution is critical. Stable knockouts and prolonged CRISPRi allow cells to adapt, accumulating compensatory mutations and epigenetic changes that obscure the gene’s immediate function. Transient, reversible perturbation reveals what the gene actually does right now.
What It Means for Functional Genomics
The platform expands perturb-seq beyond Cas9 for the first time, bringing Cas12a’s natural advantages — particularly its multiplexing capability — into the single-cell functional genomics toolkit. For complex biological processes like cellular differentiation, drug response, and disease mechanisms, the ability to simultaneously perturb multiple genes in the same cell and read out the transcriptional consequences at single-cell resolution is a significant advance.
The degron system also opens the door to genetic screens with temporal control — asking not just “what happens when this gene is off” but “what happens when we turn it back on.” This is particularly relevant for studying gene essentiality: a gene may be required for a cell to reach a certain state but dispensable once that state is achieved. Tunable CRISPRi can distinguish these scenarios.
The team has also demonstrated the platform with HyperLbCas12a, an enhanced variant of the Cas12a enzyme from Lachnospiraceae bacterium, which shows improved activity. The GEO dataset (GSE283574) accompanying the paper provides single-cell transcriptomic profiles validating the system’s performance.
The Bigger Picture
Cas12a has long been the “other” CRISPR system — powerful but finicky, promising but underutilized. This work removes the key obstacle that kept it out of perturb-seq, and adds a temporal control dimension that even Cas9 systems cannot easily replicate. For a field that has been dominated by a single tool for a decade, the arrival of a complementary platform with orthogonal capabilities is a welcome development.
Functional genomics is moving toward more complex, more dynamic, and more physiologically relevant models — organoids, primary cells, in vivo screens. Tools that offer tunable, reversible, multiplexed perturbation at single-cell resolution will be essential for that next generation of experiments. Cas12a, it appears, is finally ready to join the party.
Source: Snetkova V, Galan C, Lopez R, et al. A tunable Cas12a platform for single-cell perturbation screening and CRISPRi. Nature Communications. 2026. DOI: 10.1038/s41467-026-73955-8. GEO Dataset: GSE283574. Additional resources: github.com/snetkovalab/cas12a-perturbseq.