An integration-defective retroviral vector transfer cassette lacking a functional polypurine tract (PPT) is provided. Also provided are isolated nucleic acids that include a heterologous nucleotide sequence, one or two retroviral long terminal repeats (LTRs), a packaging signal, a rev responsive element, and a eukaryotic promoter, wherein the nucleic acid lacks a functional PPT; vectors that include the disclosed isolated nucleic acids; recombinant retroviral particles and mRNAs thereof; retroviral vector kits; and methods for producing integration-defective vector particles, achieving gene expression of a nucleotide sequence of interest, and inserting a nucleotide sequence of interest into a host cell genome in a site-specific or non-specific manner.