Kajii E, Umenishi F, Omi T, Ikemoto S
Department of Legal Medicine and Human Genetics, Jichi Medical School, Tochigi, Japan.
Hum Genet. 1995 Jun;95(6):657-65. doi: 10.1007/BF00209483.
The Rhesus (Rh) blood group system shows complex polymorphisms in the human. Some of the heterogeneity may be generated by alternative RNA splicing. For a systematic analysis of Rh-related mRNA isoforms expressed in reticulocytes, we isolated mRNA, which was then reverse transcribed and amplified by the polymerase chain reaction (PCR) to give Rh-related cDNAs of two segments of 704 bp and 975 bp. The PCR amplification of the 5'-region yielded a single PCR product, whereas a complex electrophoretic pattern of PCR bands was derived from the 3'-region. A highly reproducible ladder of multiple additional bands migrated below the PCR products corresponding to the full-size cDNAs for RhPI and RhPII and encoding two different Rh polypeptides. Eleven and five truncated isoforms of the RhPI and RhPII cDNAs, respectively, were identified in the PCR products. These isoforms appear to be generated by combinatorial splicing of six RhPI and three RhPII exons. Our results suggest that the Rh-related polypeptides consist of a mixture of RhPI and RhPII polypeptide isoforms differing at the C terminus. Multiple RNA splicing pathways are thus operative in the two Rh-related genes even within a single cell lineage of human erythroid cells.
恒河猴（Rh）血型系统在人类中表现出复杂的多态性。其中一些异质性可能是由可变RNA剪接产生的。为了系统分析网织红细胞中表达的Rh相关mRNA异构体，我们分离了mRNA，然后通过聚合酶链反应（PCR）进行逆转录和扩增，得到了704 bp和975 bp两个片段的Rh相关cDNA。5'区域的PCR扩增产生了单一的PCR产物，而3'区域则产生了复杂的PCR条带电泳图谱。在对应于RhPI和RhPII全长cDNA并编码两种不同Rh多肽的PCR产物下方，有一个高度可重复的多条额外条带梯状图谱。在PCR产物中分别鉴定出了11种RhPI cDNA截短异构体和5种RhPII cDNA截短异构体。这些异构体似乎是由6个RhPI外显子和3个RhPII外显子的组合剪接产生的。我们的结果表明，Rh相关多肽由C末端不同的RhPI和RhPII多肽异构体混合物组成。因此，即使在人类红细胞的单个细胞谱系中，多个RNA剪接途径也在两个Rh相关基因中起作用。
