SEQUENCE OF A PUTATIVE HUMAN HOUSEKEEPING GENE (HK33) LOCALIZED ON CHROMOSOME-1

A gene (Hk33) localized on human chromosome 1 has been detected by cro ssreaction of its fusion protein with a monospecific antiserum directe d against human vitamin-D-binding protein (hDBP; group-specific compon ent). Its cDNA sequence analysis showed no evident homologies neither to the sequence encoding hDBP nor to any other sequence. The largest c DNA clone of 3.2 kb includes a 897-bp coding region and a large 3' unt ranslated region with at least four polyadenylation sites. Further cDN A amplification using PCR demonstrated a total cDNA length of approx. 3.7 kb. Northern blot analysis revealed signals at about 2.2-2.5 kb an d 4.0 kb, the shorter transcripts representing mRNAs using one of the two polyadenylation sites at about 2.0 kb. Synthesis of the 299-amino- acid polypeptide (33 kDa) in the bacterial host, with subsequent Weste rn blot analysis, verified the sequence-specific recognition by the hD BP-specific antiserum. The search of protein databanks revealed no hom ology of HK33 to any known sequence. Since the gene is transcribed in all cells and tissues tested so far, it is a strong candidate for anot her housekeeping gene.