Expression of SNC73, a transcript of the immunoglobulin alpha-1 gene, in human epithelial carcinomas.
OBJECTIVE
To investigate the expression of SNC73, a trans-cript of the immunoglobulin alpha-1 gene (IgA1-H chain), in human epithelia-derived tumor cells.


METHODS
Total RNAs and cell lysates were prepared from five different human epithelial cell lines derived from lung, stomach, liver, skin, and breast, respectively. RT-PCR and immunoblot analysis of these five cell lines were done. Both RT-PCR and immunochemistry were used to detect the expression of SNC73 in these cell lines. We also examined the expression of SNC73 in normal epithelial cells of colon mucosa by in situ hybridization. RT-PCR and immunoblot analysis were used to determine whether the recombination activating gene1/2 (RAG1 and RAG2) is present. The expression of three immunoglobulin transcription factors, EBF, E2A and Pax5, and the heavy chain of IgA1 and two types of light chains of immunoglobulin (kappa and lambda) in the aforementioned cell lines were analyzed by RT-PCR and immunochemistry, respectively. All the RT-PCR products were analyzed by sequencing.


RESULTS
The results of RT-PCR and immunochemistry showed that both mRNA and protein of SNC73 were expressed in five human epithelia-derived cancer cell lines. These data were further confirmed in the normal epithelial cells of colon mucosa by in situ hybridization. Also, the heavy chain of IgA1 and kappa light chain were detected in these cells, but no lambda light chain was obse-rved. Both RAG1 and RAG2 were expressed in these human epithelia-derived cancer cell lines and the sequence was identical to that expressed in pre-B and pre-T cells. In addition to RAG1 and RAG2, the mRNA in one of the immunoglobulin transcription factors, EBF, was also detected in these cell lines, and Pax5 was only expressed in SW480 cells, but no expression of E2A was observed in all the five cell lines.


CONCLUSIONS
Immunoglobulin A1 is originally expressed and V(D)J recombination machine is also present in non-lymphoid cells, suggesting that V(D)J recombination machine mediates the assembly of immunoglobulin A1 in non-lymphoid cells as in pre-lymphocytes.
Geng
Li-Yi
LY
Cancer Institute, Zhejiang University School of Medicine, The Second Affiliated Teaching Hospital, 88 Jiefang Road, Hangzhou 310009, Zhejiang Province, China.
Shi
Zheng-Zhen
ZZ
Dong
Qi
Q
Cai
Xin-Han
XH
Zhang
Yan-Ming
YM
Cao
Wei
W
Peng
Jia-Ping
JP
Fang
Yong-Ming
YM
Zheng
Lei
L
Zheng
Shu
S
D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D003106:Colon / Q000378:metabolism / Q000473:pathology; D015179:Colorectal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006367:HeLa Cells; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007136:Immunoglobulins / Q000235:genetics / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism / Q000473:pathology; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D051757:PAX5 Transcription Factor / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D002583:Uterine Cervical Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D050441:VDJ Exons / Q000235:genetics
D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D007136:Immunoglobulins; D009687:Nuclear Proteins; D051757:PAX5 Transcription Factor; D015534:Trans-Activators; C081976:EBF1 protein, human; C497281:PAX5 protein, human; C499311:RAG2 protein, human; C452824:IGHA1 protein, human; C064658:RAG-1 protein