Ann D K, Smith M K, Carlson D M
Department of Biochemistry and Biophysics, University of California, Davis 95616.
J Biol Chem. 1988 Aug 5;263(22):10887-93.
Proline-rich proteins (PRPs) in the salivary glands of mice, rats, and hamsters are encoded by tissue-specific inducible multigene families. Mouse PRP genes are located on chromosome 8, and transcription is dramatically induced (about 70-fold) by isoproterenol treatment. Clones containing two nonallelic PRP genes (MP2 and M14) were isolated from cosmid and phage libraries of CD-1 mouse genomic DNA. The cloned regions comprise a contiguous block of 77 kilobase pairs of the mouse genome. Restriction mapping established the physical lineage of PRP genes MP2 and M14, and they are tandemly arrayed. The DNA sequence analysis presented in this report suggests that genes M14 and MP2 (Ann, D. K., and Carlson, D. M. (1985) J. Biol. Chem. 260, 15863-15872) arose via a gene duplication of a common ancestor. Two major differences between M14 and MP2 were observed. PRP gene MP2 has 13 tandemly arrayed 42-nucleotide repeats in exon II, whereas M14 has 17 repeats, and PRP gene M14 has an insertion by transposition of a 2-kilobase pair member of the long interspersed repeated DNA (LINE) family (LIMd) into intron I. The evolution of this PRP multigene family has been dominated by intra-exonic amplification of repeating nucleotide units coding for these and other proline-rich repeated peptides and by gene duplication. The LIMd element gives rise to heterogenous EcoRI, BamHI, and HindIII restriction enzyme patterns, and this insertion is also present in BALB/c, C57BL/6J, and DBA/2J mice.
小鼠、大鼠和仓鼠唾液腺中的富含脯氨酸蛋白（PRP）由组织特异性可诱导多基因家族编码。小鼠PRP基因位于8号染色体上，异丙肾上腺素处理可显著诱导转录（约70倍）。从CD-1小鼠基因组DNA的黏粒和噬菌体文库中分离出包含两个非等位PRP基因（MP2和M14）的克隆。克隆区域包含小鼠基因组中一个77千碱基对的连续片段。限制性图谱确定了PRP基因MP2和M14的物理谱系，它们是串联排列的。本报告中的DNA序列分析表明，M14和MP2基因（Ann, D. K., and Carlson, D. M. (1985) J. Biol. Chem. 260, 15863 - 15872）是通过一个共同祖先的基因复制产生的。观察到M14和MP2之间有两个主要差异。PRP基因MP2在外显子II中有13个串联排列的42个核苷酸的重复序列，而M14有17个重复序列，并且PRP基因M14通过长散在重复DNA（LINE）家族（LIMd）的一个2千碱基对成员转座插入到内含子I中。这个PRP多基因家族的进化主要由编码这些和其他富含脯氨酸重复肽的重复核苷酸单元的外显子内扩增以及基因复制主导。LIMd元件产生了异质的EcoRI、BamHI和HindIII限制性酶切图谱，并且这种插入在BALB/c、C57BL/6J和DBA/2J小鼠中也存在。
