EMBO reports publishes both long- and short-format papers that communicate major findings in all areas of molecular-, cell- and developmental-biology, offering novel physiological, functional insight that is robustly documented by independent lines of evidence. The journal also welcomes studies that confirm important findings, refute prominent claims in the literature, as well as null data on important, open questions in the biosciences. See also Publishing unpredictable research outcomes.
Papers can be in any area of biology, particularly including:

Membranes & Transport
Cell & Tissue Architecture
Signal Transduction
Chromatin & Transcription
RNA
Proteins
Cell Cycle
Genome Stability & Dynamics
Development
Differentiation & Death
Cellular Metabolism
Ageing
Neuroscience
Immunology
Plant Biology
Microbiology & Pathogens
Molecular Biology of Disease
Genomic & Computational Biology
Structural Biology
Evolution
Ecology & Environmental Science
Biotechnology