Hex1: a new human Rad2 nuclease family member with homology to yeast exonuclease 1.
Nucleolytic processing of chromosomal DNA is required in operations such as DNA repair, recombination and replication. We have identified a human gene, named HEX1 forhumanexonuclease 1, by searching the EST database for cDNAs that encode a homolog to the Saccharomyces cerevisiae EXO1 gene product. Based on its homology to this and other DNA repair proteins of the Rad2 family, most notably Schizosaccharomyces pombe exonuclease 1 (Exo1), Hex1 presumably functions as a nuclease in aspects of recombination or mismatch repair. Similar to the yeast proteins, recombinant Hex1 exhibits a 5'-->3' exonuclease activity. Northern blot analysis revealed that HEX1 expression is highest in fetal liver and adult bone marrow, suggesting that the encoded protein may operate prominently in processes specific to hemopoietic stem cell development. HEX1 gene equivalents were found in all vertebrates examined. The human gene includes 14 exons and 13 introns that span approximately 42 kb of genomic DNA and maps to the chromosomal position 1q42-43, a region lost in some cases of acute leukemia and in several solid tumors.
Biology and Biotechnology Research Program, L-452, Lawrence Livermore National Laboratory, Livermore, CA 94551, USA. wilson61@llnl.gov
D M
DM
Wilson
J P
JP
Carney
M A
MA
Coleman
A W
AW
Adamson
M
M
Christensen
J E
JE
Lamerdin
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D002878:Chromosomes, Human, Pair 1 / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D045643:DNA Repair Enzymes; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases / Q000235:genetics* / Q000378:metabolism; D005091:Exons; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007438:Introns; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000201:enzymology / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000201:enzymology / Q000235:genetics; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; C073998:RAD2 protein, S cerevisiae; C114331:EXO1 protein, human; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases; C028450:exodeoxyribonuclease I; D045643:DNA Repair Enzymes