RT Journal
A1 Oyama, Masaaki
A1 Itagaki, Chiharu
A1 Hata, Hiroko
A1 Suzuki, Yutaka
A1 Izumi, Tomonori
A1 Natsume, Tohru
A1 Isobe, Toshiaki
A1 Sugano, Sumio
T1 Analysis of Small Human Proteins Reveals the Translation of Upstream Open Reading Frames of mRNAs
JF Genome Research 
JO Genome Research 
YR 2004 
FD October 15 
VO 14 
IS 10b 
SP 2048 
OP 2052 
DO 10.1101/gr.2384604 
UL http://genome.cshlp.org/content/14/10b/2048.abstract 
AB To find novel short coding sequences from accumulated full-length cDNA sequences, proteomic analysis of small proteins expressed in human leukemia K562 cells was performed using high-resolution nanoflow liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Our analysis led to the identification of 54 proteins not more than 100 amino acids in length, including four novel ones. These novel short coding sequences were all located upstream of the longest open reading frame (ORF) of the corresponding cDNA. Our findings indicate that the translation of short ORFs occurs in vivo whether or not there exists a longer coding region in the downstream of the mRNA. This investigation provides the first direct evidence of translation of upstream ORFs in human cells, which could greatly change the current outline of the human proteome.