This is the twice-per-month electronic newsletter for basic, preclinical and translational research news related to the Johns Hopkins School of Medicine. Please forward freely. Direct comments or questions to Joanna Downer, PhD, in the Office of Corporate Communications (410-614-5105, jdowner1@jhmi.edu).
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*** Basic Science Town Meeting June 30 at 2 pm ***
IN THIS ISSUE:
RESEARCH HIGHLIGHTS:
+ In Lab, Stem Cells Mirror Normal Developmental Steps
+ Myc Controls MicroRNA Expression, Suggesting Link to Cancer
+ Cell Division Machinery Controls Immune Cells' Genetic Rearrangement
NEWS BRIEFS:
Basic Science Town Meeting June 30
Save the Date: 100+ Women Professors Celebration Nov. 1
IN THE NEWS:
James Hildreth in the Ashland City Times
Aravinda Chakravarti and Andrew Feinberg on National Public Radio
Solomon Snyder and Chi Dang in the Baltimore Business Journal
Ronald Schnaar in the Baltimore Sun
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Do you have an interesting research finding about one month from publication or presentation? Send manuscripts to Joanna Downer at jdowner1@jhmi.edu or fax to 410-614-8951. Information about awards and honors received by laboratory personnel and others is welcomed also.
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RESEARCH HIGHLIGHTS:
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6/1/05
In Lab, Stem Cells Mirror Normal Developmental Steps
Scientists have developed a way to study the earliest steps of human blood development using human embryonic stem cells grown in a lab dish.
Online in the journal Blood, Hopkins scientists and colleagues from the University of Pittsburgh School of Medicine report observing three distinct steps taken by the stem cells on their way to becoming blood cells. These steps correlate with what is already known about early stages of human blood cell development in embryos in the womb, the scientists say.
"We've captured these phases of stem cell specialization, or differentiation, in a dish," says Elias Zambidis, MD, PhD, assistant professor of pediatrics and oncology in the Johns Hopkins School of Medicine. "Now we can study these phases and hopefully help solve the Rubik's Cube of how human development works."
Without any chemical manipulation or stimulation, the clusters of human stem cells first became colonies of cells that can produce endothelium, the tissue that makes up the circulatory system. These colonies can then also form the precursors of blood cells, in a structure similar to the yolk sac of human embryos. Finally, some of the cells in the colonies form blood cells similar to those found in the liver and bone marrow of a developing fetus, making it simple for the researchers to pick out the blood cells for further investigation.
http://www.hopkinsmedicine.org/Press_releases/2005/06_20_05.html
Blood. (Published online April 15, 2005)
http://www.bloodjournal.org/cgi/content/abstract/2004-11-4522v1
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6/8/05
Myc Controls MicroRNA Expression, Suggesting Link to Cancer
Ribonucleic acid, or RNA, has long been viewed as a mere translation service for getting DNA’s blueprint to make the proteins that are cells' workhorses. But new evidence shows that tiny bits of RNA not used make proteins actually play central roles in normal biology and in the development of cancer.
"Scientists have known for a few years that production of microRNAs is only supposed to happen at certain times and in certain tissues, but no one had been able to identify what controlled the timing," says Joshua Mendell, MD, PhD, assistant professor in the McKusick-Nathans Institute of Genetic Medicine. "We've identified the first such controller, a well-studied protein called Myc."
The Myc protein (pronounced "mick") regulates the expression of about 10 percent to 15 percent of the genes in the human genome, and is faulty and overactive in many human cancer cells.
Given Myc's known roles, Mendell, Kathryn O'Donnell, Chi Dang and their colleagues tested human cells to see whether changes in the amount of Myc affected levels of any of the more than 200 known microRNAs. Their experiments showed that Myc directly controls the gene for a set of six microRNAs in a region of chromosome 13 already tied to the development of human lymphoma. The microRNAs, in turn, control the expression of other genes.
The work from investigators at Johns Hopkins is one of three papers on microRNAs in the June 9 issue of Nature. Together, the three papers suggest an important role for microRNAs in cancer development.
http://www.hopkinsmedicine.org/Press_releases/2005/06_08a_05.html
Nature 9 June 2005;435(7043):839-843.
http://www.nature.com/nature/journal/v435/n7043/full/nature03677.html
See a related News & Views and related papers in the same issue:
http://dx.doi.org/10.1038/435745a
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6/10/05
Cell Division Machinery Controls Immune Cells' Genetic Rearrangement
The basics of cell division are the same almost all mammalian cells, but there's a heck of a lot more going on in immune cells, Johns Hopkins scientists have discovered.
All dividing cells have to faithfully copy their DNA so that both new cells get the same information, and immune cells are no exception. But only immune cells must do some genetic rearranging -- using V(D)J recombination -- so they can make the endless variety of antibodies needed to fight infection and detect foreign proteins. If this recombination happens at the wrong time or interrupts the wrong genes, lymphoma may result. No one had tied this process to the cell cycle, however.
Writing in the June 10 issue of Molecular Cell, researchers from Johns Hopkins report that a protein called Skp2 that normally launches the DNA-copying machinery to start cell division also brings recombination to a close, intricately connecting the two processes.
"This form of recombination is essentially a step in cell division in these immune cells," says Stephen Desiderio, MD, PhD, professor of molecular biology and genetics in Johns Hopkins' Institute for Basic Biomedical Sciences, which he directs. "Our guess is that the cell uses the same protein to start DNA copying and end recombination in order to prevent breaks from happening at a time when the repair can't be made."
http://www.hopkinsmedicine.org/Press_releases/2005/06_09b_05.html
Mol Cell 10 June 2005;18(6):699-709.
http://dx.doi.org/10.1016/j.molcel.2005.05.011
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NEWS BRIEFS:
Basic Science Town Meeting June 30 -- The next Basic Science Town Meeting will be Thursday, June 30, at 2 p.m. in Preclinical Teaching Building Room 517. Among the topics to be discussed are the Life Sciences Park and curriculum reform.
Save the Date: 100+ Women Professors Celebration Nov. 1 -- On Tuesday, Nov. 1, The Johns Hopkins University School of Medicine, the Office of the Dean and the Women's Leadership Council will host a celebration for reaching the milestone of having more than 100 women faculty promoted to the rank of professor since the school's founding in 1893. The event will also honor the legacy of Mary Elizabeth Garrett, who provided the endowment to fund the medical school and who insisted women be admitted from the very beginning. Linda Buck, PhD, 2004 Nobel Laureate in Medicine, is confirmed as a keynote speaker. Keep an eye on http://www.hopkinsmedicine.org/wlc for more information.
James Hildreth on moving to Meharry Medical College, in the Ashland (Tenn.) City Times. "Noted HIV/AIDS researcher to bring his work, team to new Meharry center," by Amber North, the Ashland City Times, June 23, 2005.
http://www.ashlandcitytimes.com/apps/pbcs.dll/article?AID=/20050623/NEWS01/506230431/1006/MTCN01
http://www.jhu.edu/clips/2005_06/23/noted.html
(Must be at a Hopkins computer to access this Clips page.)
Aravinda Chakravarti and Andrew Feinberg on stem cells' genetics, on National Public Radio. "Scientists see defects in lab-grown stem cells," by Joe Palca, National Public Radio, June 22, 2005.
http://www.npr.org/templates/story/story.php?storyId=4713696
http://www.jhu.edu/clips/2005_06/22/cells.html
(Must be at a Hopkins computer to access this Clips page.)
Solomon Snyder and Chi Dang on the city's Life Sciences Park, in the Baltimore Business Journal. "Biopark's future depends on 'bringing in right companies,'" by Alan Zibel, Baltimore Business Journal, June 17, 2005.
http://baltimore.bizjournals.com/baltimore/stories/2005/06/20/story4.html
http://www.jhu.edu/clips/2005_06/20/bioparks.html
(Must be at a Hopkins computer to access this Clips page.)
Ronald Schnaar on the survey of scientists' behaviors, in the Baltimore Sun. "Unreliable account of scientific scruples," Letter to the Editor, The Baltimore Sun, June 18, 2005.
http://www.baltimoresun.com/news/opinion/oped/bal-ed.le.18jjun18,1,1524738.story?ctrack=1&cset=true
http://www.jhu.edu/clips/2005_06/03/drawn.html
(Must be at a Hopkins computer to access this Clips page.)
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John Sales contributed to the Research Highlights for this issue.
Find "Change" and "Basics" online from a Hopkins computer:
http://www.insidehopkinsmedicine.org/change
Visit the "Research WebNotes" newsletter online:
http://www.hopkinsmedicine.org/webnotes/
For more news from Hopkins, see:
http://www.hopkinsmedicine.org/Press_releases/index.html
Upcoming lectures and seminars:
http://www.hopkinsmedicine.org/faculty_staff/scicalendar.html
Find other news stories about Hopkins at:
http://www.insidehopkinsmedicine.org and click on "News Clips"
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--JHMI--
