Fukuoka S, Scheele G A
Laboratory of Cell and Molecular Biology, Charles A. Dana Research Institute, Beth Israel Hospital, Boston, Massachusetts.
Pancreas. 1990;5(1):1-7. doi: 10.1097/00006676-199001000-00001.
cDNA transcripts encoding rat monitor peptide (MP) have been cloned from a lambda-ZAP-II phage library using minimal specific amino acid sequence (six residues), the polymerase chain reaction (PCR), and multivalent PCR probes to distinguish MP transcripts from those that encode a closely related peptide, pancreatic secretory trypsin inhibitor. DNA sequence analysis of 3 cDNA transcripts, MP1-3, revealed the complete amino acid sequence of the prepeptide (79 residues) including an 18-residue hydrophobic signal sequence at the NH2 terminus. Sequence divergence in both coding and 3' noncoding regions indicates a potential exon-exon junction with alternative splicing, which results in a truncated peptide with Arg 58 at the COOH terminus as well as alternative selection of poly(A) signals, respectively. The 5' nontranslated region of MP1 mRNA (282 nucleotides (nt] contains four upstream ATGs. Conserved structure between MP and anionic trypsinogen mRNAs within 9 nt immediately upstream of the AUG initiation codon may be involved in coupling the expression of MP with anionic trypsinogen, a condition which appears to be required to monitor the intake of dietary protein in the rat.
已使用最小特异性氨基酸序列（六个残基）、聚合酶链反应（PCR）和多价PCR探针，从λ-ZAP-II噬菌体文库中克隆出编码大鼠监测肽（MP）的cDNA转录本，以区分MP转录本与编码密切相关肽——胰腺分泌性胰蛋白酶抑制剂的转录本。对3个cDNA转录本MP1 - 3进行DNA序列分析，揭示了前肽（79个残基）的完整氨基酸序列，包括在NH2末端的一个18个残基的疏水信号序列。编码区和3'非编码区的序列差异表明存在一个潜在的外显子-外显子连接，伴有可变剪接，这分别导致在COOH末端产生一个带有Arg 58的截短肽以及多聚腺苷酸化信号的可变选择。MP1 mRNA的5'非翻译区（282个核苷酸（nt））包含四个上游ATG。在AUG起始密码子上游紧邻的9 nt内，MP与阴离子胰蛋白酶原mRNA之间的保守结构可能参与将MP的表达与阴离子胰蛋白酶原偶联，这种情况似乎是监测大鼠膳食蛋白质摄入量所必需的条件。
