The present invention provides HIV-derived lentivectors which are safe, highly efficient, and very potent for expressing transgenes for human gene therapy, especially, in human hematopoietic progenitor cells as well as in all other blood cell derivatives. The lentiviral vectors comprise promoters active to promote expression specific to cell types or tissues. Further, promoters are providing that are amenable to control by activators, enhancers, or repressors. These vectors are in a self-inactivating configuration for biosaftey. Additional promoters are also described. The vectors can also comprise additional transcription enhancing elements such as the wood chuck hepatitis virus post-transcriptional regulatory element, without any decrease in the specificity or control exerted by the promoters. These vectors therefore provide useful tools for genetic treatments such as inherited and acquired lympho-hematological disorders, gene-therapies for cancers especially the hematological cancers, as well as for the study of hematopoiesis via lentivector-mediated modification of human HSCs.