Figure 1.

Scheme of light triggered signals affecting different aspects of nuclear gene expression. Photoreceptor proteins like phytochromes and cryptochromes absorb specific light wavelengths and transduce these signals into chromatin, transcriptional and post-transcriptional changes (see text for further details). The chloroplast is also able to act as a light sensor. Chloroplast derived retrograde signals, longer known for transcriptional regulation, are also able to regulate alternative splicing decisions in the nucleus.