Novel region within the V kappa gene promoter is responsible for tissue and stage-specific expression of immunoglobulin genes in human lymphoid neoplasms.

Immunoglobulin gene-specific transacting factors have been shown to play a role in lymphoid tissue-specific expression of immunoglobulin genes. The role of these factors in B-cell differentiation and stage-specific expression of these genes is, however, not fully understood. We have used a model of human lymphoid neoplasia to address this question. Different fragments of unrearranged human variable region of immunoglobulin kappa gene (V kappa) were used for cell-free in vitro transcription and DNA mobility shift assays. Previously described enhancement of in vitro transcription that was only seen with nuclear extracts derived from B-cell neoplasms corresponding to the late stages of B-cell differentiation was shown to be dependent on the actions of these factor(s) on the DNA region within the V kappa gene promoter. This region is located within the 920 bp fragment located 210 bp upstream from the coding region and this fragment represents a possible novel DNA region, which plays a role in the stage- and tissue-specific expression of immunoglobulin genes.