کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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5917491 | 1570734 | 2011 | 7 صفحه PDF | دانلود رایگان |

The immunoglobulin heavy (Igh) chain locus is subject to precisely regulated processes, such as variable region gene formation through recombination of variable (VH), diversity (DH), and joining (JH) segments, class switching and somatic hypermutation. The 3â² regulatory region (3â² RR) is a key regulator of the Igh locus, and, as revealed by deletions in mouse plasma cell lines and mice, is required for IgH expression as well as class switching. One of the mechanisms by which the 3â² RR regulates its targets is through long-range physical interactions. Such interactions between elements of the 3â² RR and a target site in the IgH transcription unit have been detected in plasma cells, and in resting and switching B cells, where they have been associated with IgH expression and class switching, respectively. Here, we report that lentiviral shRNA knockdown of transcription factors, CTCF, Oct-2, or OBF-1/OCA-B, had no discernible defects in loop formation or H chain expression in plasma cells. JH-3â² RR interactions in pre-B cell lines were specifically associated with IgH expression. JH-3â² RR interactions were not detected in either Pax5-deficient or RAG-deficient pro-B cells, but were apparent in an Abelson-derived pro-B cell line. These observations imply that the 3â² RR has different loop interactions with target Igh sequences at different stages of B cell development and Igh regulation.
⺠JH-3â² RR interactions are essential for IgH expression in plasma cells. ⺠These interactions can be independent of CTCF or Oct-2/OBF-1. ⺠JH-3â² RR interactions on the expressed allele in a pre-B cell line. ⺠JH3-3â² RR interactions detected in Abelson virus-transformed pro-B cell line. ⺠JH3-3â² RR interactions not detected in RAGâ/â or Pax5â/â pro-B cells.
Journal: Molecular Immunology - Volume 49, Issues 1â2, OctoberâNovember 2011, Pages 297-303