May function as a transcription factor involved in light regulation. Binds and affects blue light regulation of the al-3 gene. Wc-1 and wc-2 interact via homologous PAS domains, bind to promoters of light regulated genes such as frq, and activate transcription. May bind directly to frq. Heterodimer of wc-1 and wc-2 (Potential). Binds to DNA. By blue light.