title: A liver X receptor (LXR)-beta alternative splicing variant (LXRBSV) is preferentially expressed in the pituitary.
abstract: We have recently reported that an alternative splicing variant of liver X receptor (LXR)-beta acts as an RNA co-activator, which is referred to as LXRBSV. The in vivo role of LXRBSV is yet to be clarified. The LXRBSV gene is expressed in various tissues including the liver and brain. We evaluated the gene expression of LXRBSV in various regions of the brain using real-time quantitative PCR assays in the current study and found that LXRBSV is abundantly expressed in the pituitary. 5'-rapid amplification of cDNA ends (5'-RACE) revealed that the transcriptional start site (TSS) of LXRBSV is located 40 base pairs (bp) downstream of LXR-beta. We prepared two promoter constructs: -1598/+35 bp and -1598/+75 bp in pGL4 for LXR-beta and LXRBSV, respectively. The latter promoter construct demonstrated significantly higher activity than the former construct in GH3 cells derived from the rat pituitary. On the contrary, the promoter activities of these two constructs were indistinguishable in Hepa1-6 cells derived from mouse hepatocytes. Furthermore, the promoter region specific for LXRBSV itself exerted promoter activity in GH3 cells but not in Hepa1-6 cells. Taken together, we have concluded that LXRBSV is preferentially transcribed and expressed in the pituitary, indicating that LXRBSV plays a role in regulating pituitary gene expression. These data provide clues to elucidating the physiological relevance of LXRBSV.
authors.affiliation: Department of Medicine and Molecular Science, Graduate School of Medicine, Gunma University, 3-39-15 Showa-machi Maebashi, Gunma 371-8511, Japan. khashi@med.gunma-u.ac.jp
authors.forename: Koshi
authors.initials: K
authors.lastname: Hashimoto
authors.forename: Emi
authors.initials: E
authors.lastname: Ishida
authors.forename: Atsuko
authors.initials: A
authors.lastname: Miura
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ozawa
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Shibusawa
authors.forename: Tetsurou
authors.initials: T
authors.lastname: Satoh
authors.forename: Shuichi
authors.initials: S
authors.lastname: Okada
authors.forename: Masanobu
authors.initials: M
authors.lastname: Yamada
authors.forename: Masatomo
authors.initials: M
authors.lastname: Mori
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D002460:Cell Line; D015870:Gene Expression; D022781:Hepatocytes / Q000378:metabolism; D006801:Humans; D000071518:Liver X Receptors; D051379:Mice; D057093:Orphan Nuclear Receptors / Q000235:genetics*; D010902:Pituitary Gland / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D051381:Rats; D024363:Transcription Initiation Site; D015533:Transcriptional Activation
chemical_list: D000071518:Liver X Receptors; D057093:Orphan Nuclear Receptors