The marine microalga Nannochloropsis sp. contains various elongases and desaturases that are critical for biosynthesis of polyunsaturated fatty acids. A full-length cDNA encoding a long-chain fatty acid elongase, named NsFAE, was cloned from Nannochloropsis sp.. The open reading frame of NsFAE (GenBank accession no. MF680548) consisted of 1068 bp and encoded a predicted protein of 355 amino acids with molecular mass 38.8 kDa. The deduced polypeptide showed 43%–44% identity to fatty acyl elongases from other algae. RT-PCR experiments indicated that the NsFAE gene exhibited the highest expression in Nannochloropsis sp. at 72 h ( i.e., during the third growth stage) and the expression was significantly lower in the other four growth stages. Plasmid p NsFAE-CRISPR and a recombinant DNA fragment (ADH 1p- NsFAE-CYCt) were transformed into Saccharomyces cerevisiae strain BY4742 using the CRISPR-Cas system. Yeast transformants containing NsFAE produced three fatty acids not normally present in wild-type BY4742–linoleic acid, linolenic acid and eicosadienoic acid-indicating that NsFAE encodes a functional elongase enzyme.