Cabin D E, Gardiner K, Reeves R H
Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
Somat Cell Mol Genet. 1996 May;22(3):167-75. doi: 10.1007/BF02369907.
The mouse Pcp4 gene is highly expressed in brain, primarily in cerebellar Purkinje cells. It maps to chromosome 16 (Chr 16), in a region of conserved synteny with human chromosome 21 (Chr 21). To further characterize PCP4 and its possible contribution to cerebellar hypoplasia in trisomy 21, or Down Syndrome (DS), we cloned and sequenced the full length human cDNA, isolated a YAC which carries the entire gene, determined the gene structure, and characterized its expression. The gene spans at least 55 kb and contains two introns, the placement of which is the same in mouse. Expression in the mouse brain during development was detected at embryonic day 10, and thereafter through development. The PCP4 YAC was placed on the human Chr 21 YAC contig by a link to a YAC carrying the markers D21S15 and D21S349. This placement distal to ETS2 was confirmed by mapping on a somatic cell hybrid panel of Chr 21 translocations. This position caused an apparent break in gene order with mouse Chr 16. However, mapping in the mouse was reassessed, and Pcp4 and a linked marker, D16Mit71, were both moved distal to Ets2, corresponding to the position of PCP4 on Chr 21.
小鼠Pcp4基因在脑中高度表达，主要存在于小脑浦肯野细胞中。它定位于16号染色体（Chr 16），在与人类21号染色体（Chr 21）保守同线性的区域。为了进一步表征PCP4及其对21三体综合征（唐氏综合征，DS）中小脑发育不全可能的作用，我们克隆并测序了全长人类cDNA，分离出一个携带完整基因的酵母人工染色体（YAC），确定了基因结构，并对其表达进行了表征。该基因跨度至少55 kb，包含两个内含子，其位置在小鼠中相同。在胚胎发育第10天及之后的发育过程中均检测到该基因在小鼠脑中的表达。通过与携带标记D21S15和D21S349的YAC建立联系，将PCP4 YAC定位到人类Chr 21 YAC重叠群上。通过在21号染色体易位的体细胞杂交板上进行定位，证实了该定位在ETS2远端。这个位置导致与小鼠Chr 16的基因顺序出现明显断裂。然而，对小鼠中的定位进行了重新评估，Pcp4和一个连锁标记D16Mit71都被移到了Ets2远端，这与PCP4在21号染色体上的位置相对应。
