Krebs C J, Pfaff D W
Laboratory of Neurobiology and Behavior, Rockefeller University, New York, NY 10021, USA.
Brain Res Mol Brain Res. 2001 Mar 31;88(1-2):144-54. doi: 10.1016/s0169-328x(01)00043-2.
Rodent female reproductive behavior is facilitated by the genomic targets of estrogen (E) and progesterone (P) in neuroendocrine regions of the brain. Using the differential display-PCR technique to identify these targets we discovered a novel hormone-sensitive mRNA in the female rat brain that is substantially reduced in the ventromedial hypothalamus (VMH) after 3 h of P treatment, following 24 h of E priming. Northern blots show that it is a single transcript of approximately 1.7 kb. The sequence of the corresponding full-length cDNA indicates that this gene is the rat homolog of mouse SCAMP-4, the fourth member identified in a family of proteins known as secretory carrier membrane proteins (SCAMPs). In situ hybridization studies show that SCAMP-4 mRNA is relatively low throughout the rat forebrain, with the highest levels observed in the VMH, habenula and hippocampus. The SCAMP-4 message is also less abundant in the habenula and VMH during proestrus, when circulating levels of E and P are at their peak, than during diestrus-1 when circulating hormone levels are low. Amino acid sequence analysis indicates that SCAMP-4 lacks the putative calcium binding and leucine zipper structures, as well as protein-protein interacting NPF domains common among most SCAMP family members, but is the only member identified to date to contain a putative protein kinase C (PKC) phosphorylation site. Fluorescent microscopy of cells transfected with a SCAMP-4/GFP fusion construct reveals distinct fluorescence in subcellular aggregates that may contain secretory vesicles. In addition to our results in the VMH, the finding of high levels of SCAMP-4 message in the habenula, a brain area rich in mast cells, together with previous reports linking mast cell secretion with courtship behavior also suggest a possible role for SCAMP-4 in reproductive behaviors associated with mast cell activity in the central nervous system (CNS).
啮齿动物的雌性生殖行为受雌激素（E）和孕激素（P）在脑内神经内分泌区域的基因组靶点调控。利用差异显示PCR技术来鉴定这些靶点，我们在雌性大鼠脑中发现了一种新的激素敏感性mRNA，在雌激素预处理24小时后，用孕激素处理3小时，腹内侧下丘脑（VMH）中的这种mRNA会大幅减少。Northern杂交显示它是一个约1.7 kb的单一转录本。相应全长cDNA的序列表明，该基因是小鼠SCAMP - 4的大鼠同源物，SCAMP - 4是在一类称为分泌载体膜蛋白（SCAMPs）的蛋白质家族中鉴定出的第四个成员。原位杂交研究表明，SCAMP - 4 mRNA在整个大鼠前脑中相对较低，在腹内侧下丘脑、缰核和海马中水平最高。在动情前期，当循环中的雌激素和孕激素水平达到峰值时，缰核和腹内侧下丘脑中的SCAMP - 4信息也比动情间期-1（此时循环激素水平较低）时少。氨基酸序列分析表明，SCAMP - 4缺乏大多数SCAMP家族成员共有的假定钙结合和亮氨酸拉链结构，以及蛋白质-蛋白质相互作用的NPF结构域，但它是迄今为止鉴定出的唯一含有假定蛋白激酶C（PKC）磷酸化位点的成员。用SCAMP - 4/GFP融合构建体转染细胞的荧光显微镜观察显示，在可能含有分泌小泡的亚细胞聚集体中有明显的荧光。除了我们在腹内侧下丘脑的研究结果外，在富含肥大细胞的脑区缰核中发现高水平的SCAMP - 4信息，以及之前将肥大细胞分泌与求偶行为联系起来的报道，也表明SCAMP - 4在与中枢神经系统（CNS）中肥大细胞活性相关的生殖行为中可能发挥作用。
