Old protein, new perspective : the role of Oct-1 during embryonic development and lymphopoiesis

B cell development consists of an ordered program of rearrangement and transcriptional events, leading ultimately to the expression of immunoglobulin (Ig) molecules. This process involves the interaction of cis acting elements with trans acting factors. The octamer element (5'ATGCAAAT-3') is conserved in Ig promoters and enhancers and is thought to be important in transcriptional regulation. To date, only two octamer-binding proteins have been identified in B cells, the ubiquitously expressed Oct-1 and the lymphoid restricted Oct-2. While biochemical evidence suggests that Oct-i and Oct-2 exhibit identical DNA binding specificity, their respective roles in vivo have not been clearly defined. B cell development proceeds normally in mice deficient for Oct-2 and the B cell specific coactivator OCA-B/OBF-1/Bob-1 but these experiments were complicated by the presence of Oct-1 in the cells. In order to understand the degree of functional redundancy shared by homologous members of this family, a genetic model of Oct-i was created using gene targeting. The targeting strategy replaced exon 3, which encodes part of the transactivation domain, with a loxP-flanked neomycin cassette in the antisense transcriptional orientation. Any potential transcript derived from the targeted allele would harbor frameshift mutations, resulting in the deletion of the DNA binding POU domain. These animals are embryonic lethal with erythropoietic defects of variable penetrance due to a selective reduction of β-globin expression. Cells derived from these embryos show a 40-fold decrease in protein activity and 30-fold decrease in total detectable Oct-i polypeptides as well as a complete lack of octamer-dependent promoter activity in vivo.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Biology.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2003

Author dc:creator

• Wang, Victoria Elizabeth, 1973-

Advisor dc:contributor.advisor

• Phillip A. Sharp.

• Biology.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/29596

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/29596