Cloning of human cDNAs for Apg-1 and Apg-2, members of the Hsp110 family, and chromosomal assignment of their genes.
In mice, the Hsp110/SSE family is composed of the heat shock protein (Hsp)110/105, Apg-1 and Apg-2. In humans, however, only the Hsp110/105 homolog has been identified as a member, and two cDNAs, Hsp70RY and HS24/p52, potentially encoding proteins structurally similar to, but smaller than, mouse Apg-2 have been reported. To clarify the membership of Hsp110 family in humans, we isolated Apg-1 and Apg-2 cDNAs from a human testis cDNA library. The human Apg-1 was 100% and 91.8% identical in length and amino acid (aa) sequence, respectively, to mouse Apg-1. Human Apg-2 was one aa shorter than and 95.5% identical in sequence to mouse Apg-2. In ECV304, human endothelial cells Apg-1 but not Apg-2 transcripts were induced in 2 h by a temperature shift from 32 degrees C to 39 degrees C. As found in mice, the response was stronger than that to a 37-42 degrees C shift. The human Apg-1 and Apg-2 genes were mapped to the chromosomal loci 4q28 and 5q23.3-q31.1, respectively, by fluorescence in-situ hybridization. We isolated cDNA and genomic clones encompassing the region critical for the difference between Apg-2 and HS24/p52. Although the primer sets used were derived from the sequences common to both cDNAs, all cDNA and genomic clones corresponded to Apg-2. Using a similar approach, the relationship between Apg-2 and Hsp70RY was assessed, and no clone corresponding to Hsp70RY was obtained. These results demonstrated that the Hsp110 family consists of at least three members, Apg-1, Apg-2 and Hsp110 in humans as well as in mice. The significance of HS24/p52 and Hsp70RY cDNAs previously reported remains to be determined.
Nonoguchi
K
K
Department of Clinical Molecular Biology, Faculty of Medicine, Kyoto University, Japan.
Itoh
K
K
Xue
J H
JH
Tokuchi
H
H
Nishiyama
H
H
Kaneko
Y
Y
Tatsumi
K
K
Okuno
H
H
Tomiwa
K
K
Fujita
J
J
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002478:Cells, Cultured; D002894:Chromosomes, Human, Pair 4; D002895:Chromosomes, Human, Pair 5; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000032:analysis*; D005786:Gene Expression Regulation; D050957:HSP110 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D012689:Sequence Homology, Nucleic Acid; D013737:Testis / Q000502:physiology
D018076:DNA, Complementary; D050957:HSP110 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C121993:HSPA4 protein, human; C490979:HSPA4L protein, human; C485680:Hspa4 protein, mouse; C099678:Hspa4l protein, mouse