Discovery of a New Pomc1Allele in the LS × SS Recombinant Inbred Strains: Relationship to Locomotor Behavior

Various lines of evidence suggest that a polymorphism in the gene for proopiomelanocortin, Pomc1, might account for some portion of the genetic variance for open-field activity in the LS × SS RI strains. To test this hypothesis, approximately 1600 bp of Pomc1was sequenced from genomic DNA of seven of the LS × SS strains. Two distinct alleles containing a total of five single-base pair differences were detected. A substitution was found in the coding region causing a Pro-to-Ser conversion, two substitutions occurred in the 3 untranslated region of the mRNA, and a substitution and a deletion were detected in the 3 untranscribed flanking region. The fragment containing the coding region substitution was sequenced in an additional 15 of the LS × SS strains. A total of 12 strains contained one form of the allele, while 10 had the other. The strain distribution pattern of open-field activity scores between the two alleles suggests that these alleles do not contribute to the genetic variation of open-field activity in the LS × SS RI strains.     

垂体特异性转录因子Pou1f1靶基因在不同证候H22荷瘤小鼠的表达特征

目的分析垂体重要功能基因及其垂体特异性转录因子(Pou1f1)靶基因在不同证候荷瘤小鼠的表达差异。方法将H22肝癌腹水细胞接种于190只昆明种小鼠腋下,并设置对照组,采用小鼠标准化四诊信息采集与辨证技术筛选典型的邪毒壅盛证、气虚证、阳气虚证、气阴阳虚证小鼠,并抽提小鼠垂体、下丘脑、肾上腺等组织RNA,采用基因芯片技术检测不同组织基因表达谱,本文重点分析不同证候垂体基因芯片数据。结果与对照组比较,垂体重要功能基因阿片促黑素皮质素原(Pomc)、生长激素(Gh)和催乳素(Prl)在早期的邪毒壅盛证和气虚证中表达下调约10%,而Pomc、Gh、Prl和促甲状腺激素β亚基(Tshb)在中晚期的阳气虚证和气阴阳虚证中表达上调30%以上。Pou1f1在垂体组织中表达最高,呈现组织特异性表达特征;垂体特异性转录因子Pou1f1和Neurod1仅在邪毒壅盛证上调,Tbx19和Egr1在不同证候中均呈现上调特征,Nr4a1、Nr4a2、Pitx1、Gata2、Nr4a3、Foxl2等基因在不同证候中均呈现下调特征。Pou1f1相关靶基因Crem、Tcf4、Rnf41、Lrpprc,Mrps18b、Eif3a、Lars,Arf4、Cep57、Vcpip1,Ptpn6、Myd88、F3,Lrrfip2、Dixdc1与Pou1f1基因表达模式类似,即在邪毒壅盛证上调。结论肿瘤状态下的不同证候小鼠,其垂体重要功能基因表达失常,垂体特异性转录因子Pou1f1及其靶基因在邪毒壅盛证具有类似的表达模式。     

R-(α)-甲基组胺对AtT20垂体瘤细胞Pomc及其转录因子表达的影响

[目的]研究R-(α)-甲基组胺[R-(α)-MeHA]对AtT20垂体瘤细胞Pomc及其转录因子表达的影响.[方法]以小鼠垂体瘤细胞(AtT20)为实验对象,分别采用0.02～12.5μmol/L R-(α)-MeHA干预AtT20细胞24h,通过MTT检测药物对细胞增殖的影响;采用0.1μmol/LR-(α)-MeHA干预AtT20细胞30min、1、2、4、8、12h等相应时间,运用ELISA方法检测细胞分泌至培养液的促肾上腺皮质激素(ACTH)含量,RT-qPCR方法检测相关基因mRNA表达,Western blot方法检测相关蛋白表达.[结果] 0.02～12.5μmol/L的R-(α)-MeHA对AtT20细胞的增殖无抑制作用更无毒性作用.0.1μmol/R-(α)-MeHA对AtT20细胞ACTH分泌功能无明显作用.与对照组比较,0.1 μmol/L R-(α)-MeHA干预AtT20细胞4h后,可增强阿片促黑素皮质素原(Pomc)基因表达、0.5μmol/L R-(α)-MeHA促进Pomc蛋白表达;此外0.1μmol/L R-(α)-MeHA干预AtT20细胞30min～12h不同时点后Pou1f1基因表达均显著上调,其中以4h最为明显,上调达3倍(P＜0.05);同样,0.1 μmol/R-(α)-MeHA作用4h也显著促进Egr1基因表达上调约2倍(P＜0.05);作用1h显著增强了Prop1基因表达,上调近4倍(P＜0.05);干预4h、8h均显著上调Foxl2基因表达,上调约3倍(P＜0.05),对Neurod1、Pitx1和Tbx19基因表达无明显影响.[结论] R-(α)-MeHA具有促进Pomc基因以及其转录因子Pou1f1、Egr1、Prop1和Foxl2的表达作用.