TSS-seq of either WT or PhyAB mutants for Red light

Alternative promoter is a potentially proteome-expanding mechanism by which multiple pre-mRNAs are transcribed from a single gene. However, its general impact on the proteome and whether this regulation is intrinsically involved in normal organismal responses, remain unclear. Here we show that the plant photoreceptor phytochrome induces genome-wide alternative promoter changes in Arabidopsis. Consequently, protein isoforms with different N-termini are produced to display light-dependent localization changes, preferentially between plastids and cytoplasm.