Liu W S, Soldatov N M, Gustavsson I, Chowdhary B P
Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Hereditas. 1998;129(2):169-75. doi: 10.1111/j.1601-5223.1998.00169.x.
Human L-type Ca2+ channel alpha 1C subunit gene (CACNL1A1) maps to the distal region of chromosome 12p13, and is composed of approximately 50 exons spanning over 150 kb of the human genome as estimated by restriction map analysis. However, the structure and the total length of the 3'-end of the gene is not clear because the size of several big introns remains unknown. Here the fiber-FISH technique was used to determine the relative order and size of eight partial genomic DNA clones from the central and 3'-terminal regions of CACNL1A1. The total physical distance of this region, including the size and gap distances between the clones were re-estimated. The results show that the physical order of the tested clones was 5'-g14-5 > g12-2 > g10-8 > g4-5 > g16-7 > g8-3 > g12-5 > g6-20-3'. Their individual sizes vary between 6.7 and 21.9 kb. Clones g6-20 and g12-5, both containing repetitive exon 45/46-like element, were found to be located within 59.1 kb downstream of g8-3 containing earlier identified polyadenylation site, i.e. 229.5 kb away from clone g14-5 (exons 10, 11). The possible implications of this structural complexity is discussed.
人类L型Ca2+通道α1C亚基基因（CACNL1A1）定位于12号染色体短臂13区的远端，根据限制性图谱分析估计，该基因由大约50个外显子组成，跨越人类基因组150 kb以上。然而，由于几个大内含子的大小尚不清楚，该基因3'端的结构和全长仍不明确。在此，采用纤维荧光原位杂交技术确定了来自CACNL1A1基因中部和3'端区域的8个部分基因组DNA克隆的相对顺序和大小。重新估计了该区域的总物理距离，包括克隆之间的大小和间隔距离。结果表明，所检测克隆的物理顺序为5'-g14-5 > g12-2 > g10-8 > g4-5 > g16-7 > g8-3 > g12-5 > g6-20-3'。它们的个体大小在6.7至21.9 kb之间变化。发现克隆g6-20和g12-5均含有重复的外显子45/46样元件，位于含有较早鉴定的多聚腺苷酸化位点的g8-3下游59.1 kb内，即距离克隆g14-5（外显子10、11）229.5 kb处。讨论了这种结构复杂性的可能影响。
