Liu L X, Xu H, Weller P F, Shi A, Debnath I
Harvard-Thorndike Laboratory, Division of Infectious Diseases, Beth Israel Hospital, Boston, MA 02115, USA.
Gene. 1997 Feb 20;186(1):1-5. doi: 10.1016/s0378-1119(96)00585-9.
Factors that influence neural growth and development in parasitic nematodes have not yet been identified. We have isolated and sequenced a Brugia malayi nematode 3.4-kb genomic DNA fragment and its corresponding cDNA, which encode a predicted protein of 138 amino acids with 52% identity and 75% similarity to the mammalian neuroglial growth factor, glia maturation factor-beta (GMF). GMF promotes the differentiation of mammalian glia and neurons and stimulates axonal regeneration. The filarial nematode gene Bmgmf for Brugia malayi glia maturation factor contains six predicted exons, with the first exon encoding only the initiation methionine. Brugia malayi GMF (BmGMF) is also related to a large family of eukaryotic actin depolymerizing factors (ADFs). Although BmGMF does not contain the consensus actin-depolymerizing motif of ADFs, it does share a similar intron exon structure, including the unusual first exon, with the unc-60 ADF gene of the nematode Caenorhabditis elegans. RT-PCR experiments reveal that BmGMF is trans-spliced with the nematode spliced leader sequence SL1 and is expressed in microfilariae but not in third-stage larvae or adult worms. We speculate that BmGMF may function as a stage-specific neuroglial growth factor.
影响寄生线虫神经生长和发育的因素尚未明确。我们已经分离并测序了一个马来布鲁线虫的3.4kb基因组DNA片段及其对应的cDNA，它们编码一种预测的138个氨基酸的蛋白质，与哺乳动物神经胶质生长因子——神经胶质成熟因子-β（GMF）具有52%的同一性和75%的相似性。GMF促进哺乳动物神经胶质和神经元的分化，并刺激轴突再生。马来布鲁线虫神经胶质成熟因子的丝虫线虫基因Bmgmf包含六个预测的外显子，第一个外显子仅编码起始甲硫氨酸。马来布鲁线虫GMF（BmGMF）也与一大类真核肌动蛋白解聚因子（ADF）相关。尽管BmGMF不包含ADF的共有肌动蛋白解聚基序，但它确实与线虫秀丽隐杆线虫的unc-60 ADF基因共享相似的内含子外显子结构，包括不寻常的第一个外显子。逆转录聚合酶链反应实验表明，BmGMF与线虫剪接前导序列SL1进行反式剪接，并在微丝蚴中表达，但在三期幼虫或成虫中不表达。我们推测BmGMF可能作为一种阶段特异性神经胶质生长因子发挥作用。
