The imprinted domain in mouse distal Chromosome 7: reagents for mutagenesis and sequencing.
The imprinted domain in mouse distal Chromosome 7: reagents for mutagenesis and sequencing.
复制标题
小鼠远端染色体 7 中的印记结构域：用于诱变和测序的试剂。
DOI：
10.1007/s003359900965
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Higgins,MJ
中科院分区：
文献类型：
--
作者：
Day,CD;Smilinich,NJ;Fitzpatrick,GV;deJong,PJ;Shows,TB;Higgins,MJ
Several lines of evidence suggest that human Chromosome (Chr) band 11p15. 5 contains genes involved in tumor suppression and embryonic growth (reviewed in Reid et al. 1997 and Cooper et al. 1998). First, rare chromosomal breakpoints in Beckwith-Wiedemann syndrome (BWS) patients and pediatric tumors map to 11p15. 5. Since BWS patients suffer from a variety of overgrowth disorders and predisposition to embryonic tumors including Wilms’ tumor (WT) and rhabdomyosarcoma, the breakpoints may disrupt developmental genes or their regulation. Second, loss of heterozygosity (LOH) in 11p15. 5 has been detected in BWS and sporadic WT cases. LOH in the same region of 11p15. 5 is also observed in a variety of adult tumors, suggesting the presence of a common tumor suppressor gene or a cluster of cancer-related genes. Third, 11p15. 5 contains at least seven imprinted genes (IPL, ORCTL2/IMPT1, p57KIP2, KvLQT1, ASCL2, IGF2, and H19) that are normally expressed primarily from one, parent-specific allele. Loss of imprinting (LOI) mutations have been detected at H19, IGF2, and to a lesser extent p57KIP2 in WT and BWS patients. The resulting abnormal expression of these genes may contribute to BWS and sporadic tumor development. Finally, studies involving the transfer of regions of 11p15. 5 into mammalian cells demonstrate tumor suppressor activity in the G401 WT cell line and growth arrest in the RD rhabdomyosarcoma cell line. To study this complex genomic region, we have previously constructed a 1 mb P1-artificial chromosome (PAC) clone contig through the relevant part of 11p15. 5 (Reid et al. 1997), identified several novel transcripts in this domain (Crider-Miller et al. 1997), and shown that at least one of these transcripts represents a new imprinted gene, ORCTL2 (Organic cation transporter-like 2; Cooper et al. 1998). Compared with human, the laboratory mouse provides many advantages for the study of tumor development and genomic imprinting. These include relatively easy access to tissue samples at various developmental stages, sophisticated tools and methods for genetic analysis, and the feasibility to carry out studies in experimental tumorigenesis. To allow investigation in the mouse, we have now constructed a complete PAC clone map through the segment of mouse distal Chr 7 syntenic to the known imprinted domain in human 11p15. 5. Constituent clones provide ready access to genomic subclones necessary for targeted mutagenesis as well as large-insert clones that carry a selectable marker in mammalian cells to facilitate transgenic and complementation studies. Furthermore, now that the sequencing of PACs in the human region (Reid et al. 1997) is near completion (McDermott Center for Human Growth and Development; http://gestec. swmed. edu/), the availability of the corresponding mouse PAC clones will provide reagents for large-scale sequencing of the mouse imprinted domain for comparative studies. We also report the mapping of the Orctl2, the mouse orthologue of ORCTL2, a novel murine gene represented by several expressed sequence tags (ESTs), as well as 10 new sequence tagged sites (STSs) corresponding to ends of PAC clone inserts. The RPCI-21 mouse (129/SvEvTACfBr) PAC library consisting of more than 125,000 clones (avg. size, 127 kb) and representing 5.3 fold coverage (http://bacpac. med. buffalo. edu/mousepac. html) was screened by hybridization of high-density colony filters (18,000 clones each) with two pools of PCR or RT-PCR products. These probes corresponded to portions of
