An RNA molecule is described comprising: (a) a coding region encoding a polypeptide； and (b) a sequence shown in SEQ ID NO: 1 or 1-4 compared to the sequence shown in SEQ ID NO: 1 upstream of said coding region One or more UTR (s) comprising a sequence that shows one substitution and results in an RNA molecule having a translation efficiency equal to or greater than that of the UTR comprising UTR comprising SEQ ID NO: 1； and / or (c) Downstream of the coding region, shows 1 to 7 substitutions compared to the sequence shown in SEQ ID NO: 2 or SEQ ID NO: 2, and has the same or higher translation efficiency as an RNA molecule containing UTR containing SEQ ID NO: 2. One or more UTR (s) comprising a sequence that results in an RNA molecule having； said polypeptide encoded by said coding region is not a cytochrome b-245 alpha polypeptide (CYBA). In addition, nucleic acid molecules encoding the RNA molecules of the present invention are described. Further described are vectors comprising the nucleic acid molecules of the invention and host cells comprising the vectors of the invention. Further described is a pharmaceutical composition comprising an RNA molecule of the present invention and optionally a pharmaceutically acceptable carrier. Further described is a kit comprising the RNA molecule of the present invention. Finally, one or more UTR (s) defined in (b) and / or (or) to increase the efficiency of translation of the coding region of the RNA molecule into a polypeptide or protein encoded by said coding region. The use of one or more UTR (s) as defined in c) is described.以下を含むRNA分子が記載される：（a）ポリペプチドをコードするコード領域；ならびに（b）前記コード領域の上流の、配列番号1に示される配列または配列番号1と比較して1～4個の置換を示し、配列番号1を含むUTRを含むRNA分子と同じかそれ以上の翻訳効率を有するRNA分子をもたらす配列を含む1つ以上のUTR（単数もしくは複数）；および／または（c）前記コード領域の下流の、配列番号2に示される配列または配列番号2と比較して1～7個の置換を示し、配列番号2を含むUTRを含むRNA分子と同じかそれ以上の翻訳効率を有するRNA分子をもたらす配列を含む1つ以上のUTR（単数もしくは複数）；前記コード領域によってコードされる前記ポリペプチドは、シトクロムb-245アルファポリペプチド（CYBA）ではない。さらに、本発明のRNA分子をコードする核酸分子が記載される。さらに、本発明の核酸分子を含むベクターおよび本発明
