The problem. Transcription factors are the master switches of gene expression, but the human set was surprisingly poorly defined: estimates of how many there are, which proteins qualify, and what each binds varied across databases. Without a curated, authoritative list, reasoning about gene regulation starts from shaky ground.

The idea. Lambert and colleagues systematically reviewed the human proteome for sequence-specific DNA-binding transcription factors, curating a definitive catalogue (~1,600) with their DNA-binding domains and, where known, their binding motifs and evidence quality. It’s a reference work — the authoritative answer to “is this protein a TF, and what does it bind?”

Why it matters. This closes the regulatory loop running through this week: ENCODE mapped regulatory elements, ATAC-seq measures which are accessible, and transcription factors are what act on them to produce the expression changes DESeq2 quantifies. When a differential-expression result points upstream to a regulator, this catalogue is where you check what that regulator is and does. It connects the “what changed” of my RNA-seq to the “what drove it.”

Verdict. Foundational as a reference resource rather than a method — its value is authority and curation. Read it to ground regulatory reasoning in a definitive list, and as the human-gene-regulation counterpart to the ENCODE/ATAC-seq assays from earlier this week.