Identification of RELMγ, a novel resistin-like molecule with a distinct expression pattern☆ ☆

Abstract We have identified RELMγ, a novel member of the resistin-like molecule/found in inflammatory zone (RELM/FIZZ) family in mice and rats. Microarray and real-time RT-PCR experiments revealed a repression of RELM γ mRNA in nasal respiratory epithelium of cigarette smoke-exposed versus untreated rats. The analysis of the physiological tissue-specific expression revealed highest expression in hematopoietic tissues, suggesting a cytokine-like role for RELMγ. RELMγ is most closely related to RELMα/FIZZ1. Despite the high similarity, the expression properties of the two genes are clearly distinct. While RELM γ (approved symbol retnlg ) is expressed in rat white adipose tissue, minute to no expression of RELM α was detected in that system. Thus, previous reports analyzing RELMα expression in rat adipose tissue might have been influenced by cross-hybridization with RELMγ. Finally we could demonstrate that white adipose tissue of mice shows strong RELM α expression but only low levels of RELM γ, indicating a species-specific gene regulation.