渗漏扫描
渗漏扫描（Leaky scanning）是真核生物细胞中核糖体（43S起始前复合物）扫描mRNA的5′非翻译区时，跳过前方的起始密码子AUG，从较下游的AUG开始转译的机制。转译一般是由mRNA上最靠5'的AUG开始，但当其周围序列配置不适合起始转译时，43S起始前复合物会跳过第一个AUG，继续往3'扫描，改由较下游的AUG开始转译蛋白质[1][2]。
渗漏扫描的机制最早由美国生物学家玛丽莲·科扎克阐明。AUG密码子在GCCRCCAUGG（Kozak序列，其中R表示A或G）中时最适合起始转译[3]，当AUG周围的序列与此不一致时，多数核糖体可能会发生渗漏扫描，即跳过该AUG，继续往下游寻找更适宜起始转译的AUG，仅有少数核糖体会在该处起始转译，因此自可能转译生成数种不同的蛋白质[4]。渗漏扫描发生于许多病毒的mRNA转译过程[5]，真核细胞自身的mRNA转译也有此机制[6][7]。
参考文献
- ^ Kozak, Marilyn. Initiation of Translation in prokaryotes and eukaryotes. Gene. 1999, 234: 187-208. doi:10.1016/s0378-1119(99)00210-3.
- ^ Herzog, Etienne.; et al. Translation of the Second Gene of Peanut Clump Virus RNA 2 Occurs by Leaky Scanning In Vitro. Virology. 1995, 208: 215-225. doi:10.1006/viro.1995.1145.
- ^ Hinnebusch, Alan. Molecular Mechanism of Scanning and Start Codon Selection in Eukaryotes. American Society for Microbiology. 2011, 75 (3): 434-467. doi:10.1128/MMBR.00008-11.
- ^ Kozak, Marilyn. Pushing the limits of the scanning mechanism of initiation of translation. Gene. 2002, 299: 1-34. doi:10.1016/s0378-1119(02)01056-9.
- ^ Ryaboba, Lyubov.; et al. Translation reinitiation and leaky scanning in plant viruses. Virus Research. 2006, 119: 52-62. doi:10.1016/j.virusres.2005.10.017.
- ^ Zhou W, Song W. Leaky scanning and reinitiation regulate BACE1 gene expression.. Mol Cell Biol. 2006, 26 (9): 3353–64. PMC 1447409
. PMID 16611980. doi:10.1128/MCB.26.9.3353-3364.2006.
- ^ Kaur C, Kumar M, Patankar S. Messenger RNAs with large numbers of upstream open reading frames are translated via leaky scanning and reinitiation in the asexual stages of Plasmodium falciparum.. Parasitology. 2020, 147 (10): 1100–1113. PMID 32450933. doi:10.1017/S0031182020000840.
