Watson C E, Davies P L
Department of Biochemistry, Queen's University, Kingston, Ont., K7L 3N6, Canada.
Biochim Biophys Acta. 1999 Mar 19;1444(3):337-45. doi: 10.1016/s0167-4781(99)00007-x.
The high molecular weight basic nuclear proteins (HMrBNPs), which are tightly bound to sperm chromatin in winter flounder, are made up of imperfect reiterations of simple peptide sequences that contain phosphorylatable DNA-binding motifs. Genomic Southern blots hybridized with probes to the coding and non-coding regions of HMrBNP mRNA showed that HMrBNP sequences form a complex multi-gene family. Previously, one gene (2B) was used to establish an evolutionary link between histone H1 and the HMrBNPs. Further examination of this complex, multi-gene family has now revealed that the majority of the HMrBNP genes are linked as 4.5 kb direct tandem repeats that each contain a 2.8 kb coding region and a 1.7 kb intergenic region (IR). These findings, combined with the cloning of the IR, established that the tandemly repeated genes lack introns and code for the abundant 3 kb HMrBNP mRNAs that produce the prominent 110 kDa HMrBNP. Southern blotting of DNAs from other righteye flounder species showed that HMrBNP multi-gene families were present in closely related species, though with substantial differences in restriction patterns and band intensities, but were not detected in more distantly related flounders. These observations are consistent with recent and rapid elaboration of the HMrBNP gene family.
在冬比目鱼中与精子染色质紧密结合的高分子量碱性核蛋白（HMrBNPs），由包含可磷酸化DNA结合基序的简单肽序列的不完全重复组成。用探针与HMrBNP mRNA的编码区和非编码区杂交的基因组Southern印迹显示，HMrBNP序列形成一个复杂的多基因家族。此前，一个基因（2B）被用于建立组蛋白H1和HMrBNPs之间的进化联系。现在对这个复杂的多基因家族的进一步研究表明，大多数HMrBNP基因以4.5 kb的直接串联重复形式相连，每个重复包含一个2.8 kb的编码区和一个1.7 kb的基因间隔区（IR）。这些发现，再加上IR的克隆，确定串联重复基因缺乏内含子，并编码产生突出的110 kDa HMrBNP的丰富的3 kb HMrBNP mRNA。对其他右眼比目鱼物种的DNA进行Southern印迹分析表明，HMrBNP多基因家族存在于亲缘关系较近的物种中，尽管在限制性图谱和条带强度上有很大差异，但在亲缘关系较远的比目鱼中未检测到。这些观察结果与HMrBNP基因家族最近的快速扩展一致。
