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Small RNAs Play Big Roles in Hematopoietic Development


Rao, Dinesh Subba (2010) Small RNAs Play Big Roles in Hematopoietic Development. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/D6GJ-4057.


The relatively recent identification of microRNAs (miRNAs) has added a new layer of complexity to our understanding of gene regulation. These small noncoding RNAs cause the downregulation of target mRNAs, leading to downstream effects. We have studied how particular miRNAs can impact hematopoietic development in mice and correlated these findings with miRNA deregulation in human disease. Specifically, we studied the role of miR-155 in myeloid cells, finding that it promoted myeloid cell expansions when induced by lipopolysaccharide and a myeloproliferative disease when constitutively expressed. Interestingly, miR-155 is overexpressed in acute myeloid leukemia, a human disease that has the proliferation of myeloid cells in common with our mouse model. miR-155 is a growth-promoting factor in cells and acts in early hematopoiesis by repressing the inositol phosphatase, SHIP1. We have also studied the role of miR-34a, a putative growth-suppressing miRNA, in hematopoietic development, finding a specific perturbation in B-cell development by gain- and loss of function analyses. In this case, the majority of the findings are attributable to repression of Foxp1, a transcription factor involved in regulation of immunoglobulin gene V(D)J recombination. Our findings show how miRNAs are integrated into developmental pathways that control hematopoiesis, and suggest that they may act as nodes of regulation during specific hematopoietic developmental processes.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:microRNA, hematopoiesis, B-lymphocyte, leukemia
Degree Grantor:California Institute of Technology
Major Option:Biology
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Baltimore, David L.
Thesis Committee:
  • Patterson, Paul H. (chair)
  • Rothenberg, Ellen V.
  • Bjorkman, Pamela J.
  • Baltimore, David L.
Defense Date:20 April 2010
Non-Caltech Author Email:drao (AT)
Funding AgencyGrant Number
National Cancer Institute1K08CA133521
American Society of HematologyUNSPECIFIED
California Institute of Regenerative Medicine Training GrantUNSPECIFIED
Record Number:CaltechTHESIS:05142010-184014918
Persistent URL:
Related URLs:
URLURL TypeDescription's website
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5810
Deposited By: Dinesh Rao
Deposited On:21 May 2010 16:25
Last Modified:08 Nov 2019 18:09

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