Structure and Function of Novel Cytokine, SDF-1

基质细胞衍生因子1α和1β是一种小型细胞因子，属于间质CXC亚家族，最初通过信号序列陷阱法从小鼠骨髓基质细胞系中分离出来。分离并鉴定了人sdf1α和sdf1β基因（SDF1A和SDF1B）的cDNA和基因组克隆。sdf1α和sdf1β的cdna分别编码89和93个氨基酸的蛋白质。sdf1α和sdf1β序列与人类的相同度超过92%。SDF1基因的基因组结构表明，人类SDF1 α和SDF1 β由一个基因编码，并通过选择性剪接产生。SDF1alpha和SDF1beta分别由3和4个外显子编码。除血细胞外，SDF1基因的普遍表达与SDF1基因5'侧区富含gc序列的存在是一致的，这是“管家”基因中经常出现的情况。虽然编码intercrine家族其他成员的基因定位在染色体4q或17q上，荧光原位杂交。强大的进化保守性和独特的SDF1基因染色体局部化表明，SDF1 α和SDF1 β可能具有不同于intercrine家族其他成员的重要功能。

Stromal cell-derived factors 1alpha and 1beta are small cytokines belonging to the intercrine CXC subfamily and originally isolated from a murine bone-marrow stroma cell line by the signal seqluence trap method. cDNA and genomic clones of human SDF1alpha and SDF1beta (SDF1A and SDF1B) were isolated and characterized. cDNAs of SDF1alpha and SDF1beta encode proteins of 89 and 93 amino acids, respectively. SDF1alpha and SDF1beta sequences are more than 92% identical to those of the human conterparts. The genomic structure of the SDF1 gene revealed that human SDF1alpha and SDF1beta are encoded by a single gene and arise by altemative splicing. SDF1alpha and SDF1beta are encoded by 3 and 4 exons, respectively. Ubiquitous expression of the SDF1 gene, except in blood cells, was consistent with the presence of the GC-rich sequence in the 5' flanking region of the SDF1 gene, as is often the case in the "house keeping" genes. Although genes encoding other members of the intercrine family are localized on chromosome 4q or 17q, fluorescence in situ hybridization. Strong evolutionary conservation and unique chromosomal lacalization of the SDF1 gene suggest that SDF1alpha and SDF1beta may have important functions distinct from those of other members of the intercrine family.