|Budget Amount *help
¥1,900,000 (Direct Cost : ¥1,900,000)
Fiscal Year 1995 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1994 : ¥1,200,000 (Direct Cost : ¥1,200,000)
We previously reported the presence of an aberrant c-kit mRNA of -3.5kb in a human colon cancer cell line, Colo201, potentially encoding a truncated form of the KIT.This transcript possibly initiates in the middle of the intron 15 of the c-kit genomic region, possibly, by utilization of an alternative promotor, resulting in the addition of 25 novel amino acids translated from a message corresponding to part of intron 16 to the N-terminus of the aberrant protein.
Here we describe the expression of the aberrant c-kit transcript in 14 gastrointestinal and 11 hematopietic tumor cell lines by RT-PCR method, and the further analysis of the PCR products was carried out.
RT-PCR products were hybridized with a full-length aberrant c-kit cDNA probe. As a result, two different products of 274 bp and 198 bp were detected in 9 cell lines, although the relative expression levels of the two bands are variable. Dominant detection of the 274bp band was observed in DLD-1, Molt4, K562, Jurkat and HEL,whereas an 198 bp band was dominantly detected in SW948, BM314, MKN28 AND MKN74.
To reveal the structure of the two PCR products, their suquence analysis was performed to show that a longer ona was exactly corresponding to the -3.5kb aberrant transcript previously reported, whereas a shorter product lacked 76 bp just upstream of the exon 16 of the c-kit gene. This missing region corresponded to the additive region of the -3.5kb aberrant transcript which encoded the N-terminal 25 novel amino acids of the truncated KIT.
These aberrant messanges may regulate the expression and functions of KIT.Transfection studies with the cDNAs for them in cell lines are now under investigation.