Allele	Mouse Lines	Rationale & Data
Opn3IKMC		Parent allele used to derive other modular alleles.
Opn3lacZ	Opn3lacZ/lacZ	Reporter null allele. Key data presented for this mouse line includes Figures 1,3, 4, 6, and 7, where we show adipocyte expression, adipocyte morphometric differences, NAD, ETC, body temperature, gene expression differences, and adipocyte specific light responses.
Opn3fl	Adipoqcre; Opn3fl/fl	Conditional deletion of Opn3 from adipocytes. Key data for this mouse line are presented in Figures 5 and 7 where we directly measure markers of lipolysis that are OPN3- and light-dependent. This allele is crucial because it permits us to focus on analyses that explore adipocyte-specific OPN3 functions. Additional data on tail temperature from Opn3fl/fl and Adipoqcre; Opn3fl/fl animals are presented in Figure S5C.
	Ucp1cre; Opn3fl/fl	Conditional deletion of Opn3 from brown adipocytes. Key data for this mouse line are presented in Figure 5E showing no difference between Opn3fl/fl and Ucp1cre; Opn3fl/fl adult mice in defended body temperature following cold exposure.
	Rxcre; Opn3fl/fl	Conditional deletion of Opn3 from retinal progenitors. Key data for this mouse line are presented in Figure S5B showing no difference in defended core body temperature between cold exposed Opn3fl/fl and Rxcre; Opn3fl/fl adult mice.
Opn3cre	Opn3cre; Ai14	In house developed and validated constitutive Cre driver line used in combination with Ai14 (Jax #007908) to characterize OPN3 expression in iscWAT and iBAT via the fluorescent tdTomato reporter. Key data presented for this line are in Figures 1l–1K.
Opn3ΔEx2	Opn3ΔEx2/ΔEx2	In house generated CRISPR-Cas9 mediated 2203 bp deletion of exon 2 of the Opn3 locus. Key data presented for this mouse line is in Figure 4B, showing persistence of defended core body temperature differences between controls and Opn3 loss-of-function animals on a congenic C57BL/6J background.