Characterization of the promoter region and oligomerization domain of H4 (D10S170), a gene frequently rearranged with the ret proto-oncogene.
PTC-1, the predominant form of PTC oncogene in human papillary thyroid carcinoma, encodes a fusion protein containing the N-terminus of H4 (D10S170) fused 5' to the ret tyrosine kinase domain. Accordingly, the PTC-1 expression is driven by the H4 gene promoter. Our study showed that H4 is expressed in various human tissues, including thyroid. Furthermore, we have localized the transcriptional start sites of H4 to a region 100 to 190 bp upstream of the translation initiation site (ATG) by primer extension assay, and the H4 promoter to a region within 259 bp upstream of the ATG site by luciferase assay. Interestingly, protein sequence analysis indicated a potential coiled-coil domain in the N-terminal region of H4. Indeed, oligomerization was demonstrated by an in vitro assay with recombinant proteins containing this region. As dimerization is considered to be a crucial step for receptor tyrosine kinase activation, we hypothesize that both unscheduled expression of ret tyrosine kinase and constitutive oligomerization of PTC-1 proteins are responsible for PTC-1 transforming activity in thyroid.
Tong
Q
Q
Department of Physiology, Ohio State University, Columbus 43210, USA.
Li
Y
Y
Smanik
P A
PA
Fithian
L J
LJ
Xing
S
S
Mazzaferri
E L
EL
Jhiang
S M
SM
D001483:Base Sequence; D002291:Carcinoma, Papillary / Q000235:genetics; D003598:Cytoskeletal Proteins; D017931:DNA Primers / Q000737:chemistry; D029721:Drosophila Proteins; D015870:Gene Expression; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D015513:Oncogene Proteins / Q000235:genetics*; D015514:Oncogene Proteins, Fusion; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011505:Protein-Tyrosine Kinases; D011506:Proteins / Q000235:genetics*; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D051096:Proto-Oncogene Proteins c-ret; D011519:Proto-Oncogenes; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*; D011993:Recombinant Fusion Proteins; D013961:Thyroid Gland / Q000378:metabolism; D013964:Thyroid Neoplasms / Q000235:genetics
C088832:CCDC6 protein, human; D003598:Cytoskeletal Proteins; D017931:DNA Primers; D029721:Drosophila Proteins; C000715470:MAS1 protein, human; D046911:Macromolecular Substances; D015513:Oncogene Proteins; D015514:Oncogene Proteins, Fusion; D011506:Proteins; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D011993:Recombinant Fusion Proteins; D011505:Protein-Tyrosine Kinases; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; C416649:Ret protein, Drosophila; C093573:ret-PTC fusion oncoproteins, human