Selective Gene Expression in Magnocellular Neurons in Rat Supraoptic Nucleus

Abstract

Oxytocin-and vasopressin-producing magnocellular neurons (MCNs) of the hypothalamo-neurohypophysial system are the only neuronal phenotypes present in the rat supraoptic nucleus (SON). Laser microdissection of the SON, extraction and T7-based amplification of its RNAs, and analysis of the resulting cDNAs by hybridization on a 35, 319 element DNA microarray have provided a detailed composite view of the gene expression profile of the MCNs. The genes expressed in the SON were compared with those expressed in a reference tissue consisting of total hypothalamus, and this "expression ratio" indicated which genes were preferentially expressed in the SON. Of the 26,000 unique genes on the array, 1385 were found to be expressed in the SON at levels more than two times greater than in the hypothalamus as a whole. Of these, 123 were expressed Ն3.4-fold higher in the SON versus hypothalamus. Most of these preferentially expressed genes were not previously known to be expressed in the MCNs. Quantitative and double-label in situ hybridization histochemistry was used selectively to confirm a number of these microarray observations and to evaluate the osmotic regulation and cell-specific expression of these genes, respectively.

A comprehensive description of the transcriptome of the hypothalamoneurohypophyseal system in euhydrated and dehydrated rats

“…Six genes are up-regulated and one is down-regulated in the SON and PVN as a consequence of dehydration. Two of the up-regulated genes, c1q domain-containing 1 and opsin 3 (encephalopsin), have previously been described as being highly expressed in the SON (23), where they are down-regulated by hypoosmolality (25) but up-regulated by a chronic hyperosmotic cue (23,25). The remaining four up-regulated genes are gonadotropin-inducible ovarian transcription factor 1 (a putative transcriptional repressor) (36), tumor necrosis factor induced protein 6 (involved in the remodeling of the extracellular matrix) (37), solute carrier family 12, member 1 (involved in the coupled electroneutral transport of Na ϩ , K ϩ , and Cl Ϫ into cells and associated with hypertension in Japanese women) (38,39) and lipocalin 2 (an intracellular chemical signal that delivers low-molecular-weight cargo) (40).…”

“…The availability of genome information and the parallel development of transcriptomic (microarray) technologies have provided the means to answer two crucial questions: (i) what genes are expressed in the different compo-nents of the NHS, namely the PVN, the SON and the neurointermediate lobe (NIL) of the pituitary gland and (ii) what genes are up-or down-regulated in these same structures after dehydration? Thus, a number of groups have started to use microarray global gene expression profiling technologies to address the question of how many of these genes are utilized by the SON (23) and how the overall pattern of gene expression is changed in the SON by osmotic cues (24,25). The physiological value of this approach has been illustrated by our recent identification of IL-6 as a secretory product of the HNS (24).…”

Depolarization and Neurotransmitter Regulation of Vasopressin Gene Expression in the Rat Suprachiasmatic NucleusIn Vitro

“…ISHH procedures were similar to those described previously Mutsuga et al, 2004). Cultured slices were fixed on the filters for 40 min in 4% buffered formaldehyde, washed in PBS, rinsed with sterile water, and then carefully removed from the filters and mounted onto positively charged slides.…”

Combining laser capture microdissection with quantitative real-time PCR: Effects of tissue manipulation on RNA quality and gene expression

“…More recent investigations have focused on applying LCM to the study of the central nervous system. These have included genome-wide gene expression analyses using DNA microarrays, as well as expression analyses of individual genes using reverse-transcriptase polymerase chain reaction (RT-PCR) (Jin et al, 1999;Kamme et al, 2003;Lu et al, 2004;Mutsuga et al, 2004;Torres-Munoz et al, 2001;Ye et al, 2003).…”