PubMed · 14348601
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H E KAY. 1965-08-28. HOW MANY CELL-GENERATIONS?. https://doi.org/10.1016/s0140-6736(65)90763-4
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Greig cephalopolysyndactyly (GCPS; OMIM 175700) is an autosomal dominant condition caused by mutations of the gene GLI3, located on 7p13. To date, several cases of deletions and/or translocations involving this locus have been reported in patients with GCPS. GLI3 is a transcription factor from the GLI-Kruppel gene family that has been implicated in three distinct entities: GCPS, Pallister-Hall syndrome, and postaxial polydactyly type A. The zinc finger protein, subfamily 1, member 1 gene (ZNFN1A1; OMIM 603023), on 7p12, codes for a lymphoid-restricted zinc finger transcription factor, ZNFN1A1, also called IKAROS, that regulates lymphocyte differentiation and has been associated with the development of childhood leukemia. We present the case of a 9-year-old Latin-American boy who was referred for stem cell transplantation because of recurrent acute lymphoblastic leukemia (ALL). On evaluation, he was found to have dysmorphic features consistent with GCPS, including a prominent forehead, down-slanting palpebral fissures, 1-2-3 toe syndactyly, broad thumbs and first toes, and mild developmental delay. He had developed ALL at 5 years of age. Chromosome analysis of bone marrow and fibroblastic cells showed an interstitial deletion of chromosome arm 7p, del(7)(p11.2p14), in 74% and 44% of the cells, respectively. We performed FISH analysis with a BAC clone containing the ZNFN1A1 gene and demonstrated that it is contained in the deleted segment. To our knowledge, this is the first report of a patient with GCPS and leukemia. We hypothesize that constitutional deletion of the ZNFN1A1 gene in this patient may have resulted in an increased risk of lymphoid malignancy.
The isolation of embryonic stem (ES) cells from human preimplantation blastocysts creates an exciting new starting point to analyze the earliest stages of human blood development. This chapter describes two methods to promote hematopoietic differentiation of human ES cells: stromal cell coculture and embryoid body formation. Better understanding of basic human hematopoiesis through the study of human ES cells will likely have future therapeutic benefits.
Human hematopoietic stem cells (HSCs) and their progenitors can be maintained in vitro in long-term bone marrow cultures (LTBMCs) in which constituent HSCs can persist within the adherent layers for up to 2 months. Media replenishment of LTBMCs has been shown to induce transition of HSCs from a quiescent state to an active cycling state. We hypothesize that the media replenishment of the LTBMCs leads to the activation of important regulatory genes uniquely involved in HSC proliferation and differentiation. To profile the gene expression changes associated with HSC activation, we performed suppression subtractive hybridization (SSH) on day 14 human LTBMCs following 1-h media replenishment and on unmanipulated controls. The generated SSH library contained 191 differentially up-regulated expressed sequence tags (ESTs), the majority corresponding to known genes related to various intracellular processes, including signal transduction pathways, protein synthesis, and cell cycle regulation. Nineteen ESTs represented previously undescribed sequences encoding proteins of unknown function. Differential up-regulation of representative genes, including IL-8, IL-1, putative cytokine 21/HC21, MAD3, and a novel EST was confirmed by semi-quantitative RT-PCR. Levels of fibronectin, G-CSF, and stem cell factor also increased in the conditioned media of LTBMCs as assessed by ELISA, indicating increased synthesis and secretion of these factors. Analysis of our library provides insights into some of the immediate early gene changes underlying the mechanisms by which the stromal elements within the LTBMCs contribute to the induction of HSC activation and provides the opportunity to identify as yet unrecognized factors regulating HSC activation in the LTBMC milieu.