Kolodrubetz D, Burgum A
Department of Microbiology, University of Texas Health Science Center, San Antonio 78284.
J Biol Chem. 1990 Feb 25;265(6):3234-9.
The nonhistone chromosomal protein NHP6 from Saccharomyces cerevisiae has been previously isolated and its amino-terminal sequence determined. In this report, synthetic oligonucleotides, designed from the limited NHP6 amino acid sequence, were used as hybridization probes to clone the NHP6A gene from a yeast genomic library. Low stringency Southern blot analysis showed that there was a second gene homologous to NHP6A. This gene, NHP6B, was also cloned and sequenced. Nucleotide sequence analysis revealed that NHP6B has six extra amino acids at its amino terminus, but that NHP6A and NHP6B match at 87% of the rest of their sequences. S1 nuclease analysis was used to show that both genes are transcribed; the major transcription start sites lie 30 bases before the first ATG codon. Interestingly, the approximately 11-kDa NHP6A and NHP6B proteins are homologous to the middle segment of the 27-kDa chromatin-associated high mobility group protein 1 from calf; NHP6A and NHP6B each have over 40% identity with this part of high mobility group protein 1. Possible functions for the NHP6 proteins are discussed in light of this homology.
酿酒酵母的非组蛋白染色体蛋白NHP6先前已被分离出来，并确定了其氨基末端序列。在本报告中，根据有限的NHP6氨基酸序列设计的合成寡核苷酸被用作杂交探针，从酵母基因组文库中克隆NHP6A基因。低严谨度的Southern印迹分析表明，存在另一个与NHP6A同源的基因。该基因NHP6B也被克隆并测序。核苷酸序列分析显示，NHP6B在其氨基末端有六个额外的氨基酸，但NHP6A和NHP6B在其余87%的序列上匹配。用S1核酸酶分析表明这两个基因都被转录；主要转录起始位点位于第一个ATG密码子之前30个碱基处。有趣的是，大约11 kDa的NHP6A和NHP6B蛋白与小牛27 kDa的染色质相关高迁移率族蛋白1的中间片段同源；NHP6A和NHP6B与高迁移率族蛋白1的这一部分各自具有超过40%的同一性。根据这种同源性讨论了NHP6蛋白的可能功能。
