ALTERNATIVE PROCESSING OF MESSENGER-RNAS ENCODING MAMMALIAN CHROMOSOMAL HIGH-MOBILITY-GROUP PROTEINS HMG-I AND HMG-Y
ALTERNATIVE PROCESSING OF MESSENGER-RNAS ENCODING MAMMALIAN CHROMOSOMAL HIGH-MOBILITY-GROUP PROTEINS HMG-I AND HMG-Y
复制标题
DOI：
10.1128/mcb.9.5.2114
复制
发表时间：
1989-05-01
影响因子：
5.3
通讯作者：
REEVES, R
中科院分区：
文献类型：
--
作者：
JOHNSON, KR;LEHN, DA;REEVES, R
高迁移率组蛋白 HMG-I 是一种已充分表征的非组蛋白染色体蛋白，优先在快速分裂的细胞中表达，与 A .cntdot 结合。体外 DNA 富含 T 区域，并且已定位于哺乳动物中期染色体的特定区域。我们从人 Raji 细胞 cDNA 文库中分离了 8 个编码 HMG-1 及其亚型 HMG-Y 的 cDNA 克隆，并在这些克隆的 5''-非翻译区中检测到核苷酸序列重排块。除了前导序列变异之外，8 个 cDNA 克隆中的 5 个在其开放阅读框 (ORF) 中具有 33 或 36 碱基对的框内删除；我们发现这个缩短的 ORF 编码 HMG-Y 蛋白亚型。我们提供的证据表明，cDNA 克隆的 5''非翻译区和 ORF 异质性是来自单个功能基因的 RNA 转录物的替代加工的结果。人类基因组中存在一些额外但可能无功能的 HMG-I 或 HMG-Y 基因拷贝；我们分离并部分测序了其中一个假基因，发现它是经过加工的 HMG-Y 逆转录假基因。
The high-mobility group protein HMG-I is a well-characterized nonhistone chromosomal protein that is preferentially expressed in rapidly dividing cells, binds to A .cntdot. T-rich regions of DNA in vitro, and has been localized to particular regions of mammalian metaphase chromosomes. We isolated eight cDNA clones encoding HMG-1 and its isoform HMG-Y from a human Raji cell cDNA library and detected blocks of nucleotide sequence rearrangements in the 5''-untranslated regions of these clones. In addition to this leader sequence variation, five of the eight cDNA clones had either a 33- or 36-base-pair in-frame deletion in their open reading frame (ORF); we found that this shortened ORF encodes the HMG-Y protein isoform. We present evidence tha the 5''-untranslated-region and ORF heterogeneity of the cDNA clones is the result of alternative processing of RNA transcripts from a single functional gene. Several additional but probably nonfunctional HMG-I or HMG-Y gene copies exist in the human genome; we isolated and partially sequenced one of these pseudogenes and found that it is a processed HMG-Y retropseudogene.