Li Aiqing, Rinehart Joseph P, Denlinger David L
Department of Entomology, Ohio State University, Columbus, OH 43210, USA.
Peptides. 2009 Mar;30(3):518-21. doi: 10.1016/j.peptides.2008.10.008. Epub 2008 Oct 21.
Suppression subtractive hybridization comparing brains from diapausing and nondiapausing pupae of the flesh fly, Sarcophaga crassipalpis, suggested that the gene encoding neuropeptide-like precursor 4 (Nplp4) was uniquely expressed during diapause. We have sequenced the full-length cDNA encoding Nplp4 and used Northern blots to further evaluate linkage to diapause. The open reading frame of this cDNA encodes a 61-amino acid residue precursor protein containing a predicted 18 residue signal peptide, one 22-amino acid and one 2-amino acid propeptides, and a 19-amino acid neuropeptide. The amino acid sequence of the precursor protein shows 64% identity to Drosophila melanogaster Nplp4; homologues of this precursor protein are not known from species other than these two flies. Nplp4 mRNA levels were quite low in nondiapausing (long day) pupae, but in contrast the gene was highly upregulated in diapausing (short day) pupae. Expression increased at the onset of diapause, remained high throughout diapause, and then decreased 2 days after diapause was terminated. Although the function of this precursor protein and the neuropeptide it yields remain unknown, this close association with diapause suggests a potential role for Nplp4 in initiating and maintaining diapause in the flesh fly.
通过抑制性消减杂交技术比较了肉蝇（Sarcophaga crassipalpis）滞育蛹和非滞育蛹的大脑，结果表明编码神经肽样前体4（Nplp4）的基因在滞育期间特异性表达。我们已对编码Nplp4的全长cDNA进行了测序，并使用Northern印迹法进一步评估其与滞育的关联。该cDNA的开放阅读框编码一个61个氨基酸残基的前体蛋白，其中包含一个预测的18个残基的信号肽、一个22个氨基酸的前肽和一个2个氨基酸的前肽，以及一个19个氨基酸的神经肽。前体蛋白的氨基酸序列与黑腹果蝇Nplp4的同一性为64%；除了这两种果蝇外，其他物种中尚未发现该前体蛋白的同源物。Nplp4 mRNA水平在非滞育（长日照）蛹中相当低，但相比之下，该基因在滞育（短日照）蛹中高度上调。在滞育开始时表达增加，在整个滞育期间保持高水平，然后在滞育结束后2天下降。尽管这种前体蛋白及其产生的神经肽的功能尚不清楚，但与滞育的这种密切关联表明Nplp4在肉蝇滞育的启动和维持中可能发挥作用。
