Molecular biology of vasoactive substances

在培养的新生儿大心室心肌细胞心肌肥厚模型中，脑钠肽（BNP） mRNA升高，并在1小时内达到最大水平，而转录抑制剂完全降低了这一水平。克隆的人BNP基因5'-侧翼区启动子活性在删除富含ct的序列（-1288 ~ -1095）后降低至30%。BNP基因被分配到人类1号染色体上。RT-PCR技术证实了两个新的人内皮素- a受体（ET-AR）基因转录本分别缺失199 bp和327 bp。缺失的序列分别对应于外显子4和外显子3和4，表明这些ET-AR转录本是由选择性RNA剪接产生的。推定的负调控区位于小鼠血管紧张素II型2 （AT_2）受体基因-453 ~ -225之间，其中确定了干扰素调节因子（IRF）结合基序。IRF-2在生长和融合的R3T3细胞中均能减弱AT2受体的表达，而IRF-1仅在融合细胞中增强AT2受体的表达。人类前列环素受体基因全长约7.0 kb，由3个外显子组成，位于第19染色体上。转录起始位点位于ATG起始密码子上游870-872 bp。1.2 kb的5'侧区缺乏传统的TATA和CCAAT盒，但它包含几个顺式作用的调控元件，包括一个倒置的CCAAT盒和两个SP-1结合位点拷贝。

Brain natriuretic peptide (BNP) mRNA increased and reached a maximal level within 1 h in a model of cardiac hypertrophy using cultured neonatal ratventricular cardiocytes, which was completely diminished by a transcriptional inhibitor. The promotor activity of the cloned 5'-flanking region of human BNP gene was reduced to 30% when the CT-rich sequences (-1288 to -1095) were deleted. The BNP gene was assigned to human chromosome 1. Two novel transcripts of the human endothelin-A receptor (ET-AR) gene contained deletions of 199 bp and 327 bp were demonstrated using RT-PCR.The deleted sequences corresponded to exon 4 and exons 3 and 4, respectively, indicating these ET-AR transcripts result from alternative RNA splicing. The putative negative regulatory region was located between -453 and -225 of mouse angiotensin II type 2 (AT_2) receptor gene, in which the interferon regulatory factor (IRF) binding motif was identified. IRF-2 attenuated the AT2 receptor expression in both growing and confluent R3T3 cells, whereas IRF-1 enhanced AT2 receptor expression in the confluent cells only. The human prostacyclin receptor gene spanned approximately 7.0 kb and was composed of three exons, which was assigned to chromosome 19. The transcription initiation sites were mapped 870-872 bp upstream to the ATG start codon. The 1.2-kb 5'-flanking region lacked conventional TATA and CCAAT boxes, but it contained several cis-acting regulatory elements including an inverted CCAAT box and two copies of SP-1 binding sites.