Gene expression profile of the third pharyngeal pouch reveals role of mesenchymal MafB in embryonic thymus development

Abstract

The thymus provides a microenvironment that induces the differentiation of T-progenitor cells into functional T cells and that establishes a diverse yet selftolerant T-cell repertoire. However, the mechanisms that lead to the development of the thymus are incompletely understood. We report herein the results of screening for genes that are expressed in the third pharyngeal pouch, which contains thymic primordium. Polymerase chain reaction (PCR)-based cDNA subtraction screening for genes expressed in microdissected tissues of the third pharyngeal pouch rather than the second pharyngeal arch yielded one transcription factor, MafB, which was predominantly expressed in CD45 ؊ IA ؊ PDGFR␣ ؉ mesenchymal cells and was detectable even in the third pharyngeal pouch of FoxN1-deficient nude mice. Interestingly, the number of CD45 ؉ cells that initially accumulated in the embryonic thymus was significantly decreased in MafB-

Mafb lineage tracing to distinguish macrophages from other immune lineages reveals dual identity of Langerhans cells

“…Our attention to faithful expression of MafB from the mutated allele was prompted by evidence that Mafb -haploinsufficient mice exhibit subtle defects in hematopoiesis (Sultana et al, 2009) and by reports that aberrant expression of that protein can severely decrease viability of the organism. The kreisler ( kr ) mutation is a radiation-induced chromosomal inversion that separates an intact Mafb transcriptional unit from putative distal enhancer elements (Cordes and Barsh, 1994).…”

Thymic epithelial cells: the multi-tasking framework of the T cell “cradle”

“…MTS20 and MTS24) that identity bipotent precursors unambiguously remain controversial [31,32,34]. It is interesting to note that the majority of TECs at these early stages express Cxcl12, Ccl25, Ccl19, Ccl21, Dll4 and Il7 [14,15,21,35,36], suggesting that early TECs may have a dual functional activity; i.e. providing key thymopoietic factors and being the precursor for prototypic mature TEC subsets (Figure 1).…”

Transcription factor MafB may play an important role in secondary hyperparathyroidism

“…The following primer pairs were used: MafB, 5'-TGAGCATGGGGCAAGAGCTG-3' and 5'-CCATCCA GTACAGGTCCTCG-3'; Ccnd1, 5'-TGACACCAATCTCCTCAACGA CC-3' and 5'-GGATGGCACAATCTCCTTCTGC-3'; Ccnd2, 5'-AG GAGAAGCTGTCCCTGATCC -3' and 5'-AGTTGCAATCATCGA CGGC -3'; PTH, 5'-GCTGGCAGTCTGTCTTCTTACCC -3' and 5'-;TG TCAGTGCCCTGCACTGTC -3'; Kl, 5'-CAAAGTCTTCGGCCTTG TTC -3' and 5'-CTCCCCAAGCAAAGTCACA -3'; and Hprt, 5'-TT GTTGTTGGATATGCCCTTGACTA-3' and 5'-AGGCAGATGGCC ACAGGACTA-3' . 22,[40][41][42] Luciferase assay To construct reporter plasmids, DNA fragments corresponding to positions À545 to þ100 in the WT and mutant murine Ccnd2 gene promoter, 22 and murine evolutionally conserved region 4 and the proximal basal PTH promoter 8 were obtained from Gene Synthesis Service (TAKARA Bio) and subcloned individually into the pGL3-Luc vector (Promega, Madison, WI). To express MafB, we used a previously described expression plasmid (pEFX3-FLAG-MafB).…”