Cloning and characterization of a cDNA encoding human differentiation antigen 5D4

A 1 846 bp cDNA is isolated from a human tonsil cell lambda gt II cDNA libr ary (ATCC No. 37546) with mAb 5D4 reactive strongly with human B cell line 3D5, but weakly with human B cell line Daudi and human T cell line Jurkat a s a probe. RT-PCR also shows a strong reaction in 3D5 cell and a weak react ion in Daudi and Jurkat cell for 5D4 mRNA. There is an open reading frame f rom 88 to 1 209 bp in 5D4 cDNA encoding a 374 AA protein. Both the Northern blot analysis and the two consecutive stop codens before start coden demon strate that the cDNA is a full-length cDNA. Secondary structure prediction suggests that there are a region from 295 to 334 AA in the protein with str ong hydrophobicity and a transmembrane helix region with high score from 31 3 to 334 AA with an orientation from the inside to the outside of the cell.