Speed limit on DNA-making sets pace for life's first steps

Speed limit on DNA-making sets pace for life's first steps
MS2 reporters show nuclei dividing at alarming rates (right) as compared to the normal zygote (left) during nuclear cleavage cycles Credit: Stanislav Y. Shvartsman

Fruit flies make for stingy mothers, imparting only a portion of the genetic building blocks their offspring need to survive. The rest must be produced by the fertilized egg in its first few steps of growth.

Scientists puzzled for two decades over this seemingly unnecessary withholding. Now researchers at Princeton University have shown that the inhibiting mechanism, controlled by an enzyme known as RNR, is actually key to the embryo's survival. Too much material early on leads to disaster for the fledgling lifeform.

"This study shows us how fragile development can be," said Stanislav Shvartsman, professor of chemical and biological engineering and the Lewis-Sigler Institute for Integrative Genomics at Princeton. "We asked the question, 'Why does the mother have to be so frugal?'" The problem led Shvartsman to test what happens when an embryo inherits an abundance of these building blocks. The answer was not pretty. "We realized, if you do not limit the supply, you create a temporal conflict that disrupts multiple processes in the embryo," he said.

In a study reported in the journal Current Biology on March 14, the team tracked two groups of flies' embryonic development: one with a normal supply of DNA building blocks, known as nucleotides, and one with around 10 times that amount. The results showed that, when more nucleotides were available to the embryo from the start, its DNA replication mechanism worked at breakneck speeds, running roughshod over the processes that followed and resulting in major defects later on.

Nareg Djabrayan, an associate research scholar at the Lewis-Sigler Institute for Integrative Genomics at Princeton and first author of the paper, likened the replication process to a machine. "When you provide that machine with too much of a certain input, its speed limit is broken," he said. "It goes too fast. And it messes with the other things that have to happen at the same time."

Speed limit on DNA-making sets pace for life's first steps
Images from a scanning electron microscope show the midline of the mutant fly (below) go sideways at morphogensis, just as the embryo begins to take shape. Compare that to the normal development at the same stage (above). Once this defect occurs, the embryo cannot develop further. Credit: Stanislav Y. Shvartsman

The problems that began in that first key step compounded through later stages. As the embryo began to take shape, its midline (the fly's analog of a spine) was catastrophically twisted.

"After that, they go kaput," Shvartsman said.

It turns out that the maternal withholding, quantified in previous work, plays a major role in the timing of early life, providing a natural limit to the pace of development. In the end, those flies that started out with a surplus of basic ingredients could not develop into a viable organism.

The findings mark a shift in thinking for researchers who study the control of genomes in transition from mother to offspring, according to cell biologist Stefano Di Talia, of Duke University. "This paper is important because it shows that tight control of nucleotide levels is not only energetically favorable but also absolutely required for to proceed normally," he said. Di Talia suggested that future studies will build on this work to learn how the timing of cell cycles impacts tissue mechanics.

In this case, the enzyme RNR—a common target in anti-cancer therapies—plays a critical role in balancing the speed of a cell's most basic processes, and by consequence, cell division. Runaway cell division and growth are the hallmarks of cancer. In addition to answering a fundamental question about early life in animals, the researchers believe this work could open new pathways to study cancer drugs in developing embryos.

The title of the research article is "Metabolic regulation of developmental cell cycles and zygotic transcription."


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Embryos rapidly outgrow mother's genetic kick-start

Journal information: Current Biology

Citation: Speed limit on DNA-making sets pace for life's first steps (2019, March 14) retrieved 23 May 2019 from https://phys.org/news/2019-03-limit-dna-making-pace-life.html
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Mar 14, 2019
"When you provide that machine with too much of a certain input, its speed limit is broken," he said. "It goes too fast. And it messes with the other things that have to happen at the same time."

A rather indirect admission that it was designed. They recognize it but cannot say it in public for fear of losing their jobs or funding or whatever.
Such it the foolishness of those who reject their Creator : "The FOOL said in his heart there is no GOD". Psalm 14:1

Mar 14, 2019
A rather indirect admission that it was designed.


How the hell did you come to that conclusion? If complex life MUST be created, what created the creator? Who do you actually think you'll convince with your fairytales and lies, freddo?

Mar 14, 2019
@fanatical fred
A rather indirect admission that
total bullsh*t
it was designed
and again, to use your own words:
This is pure science fiction. Not observed, not verifiable, not repeatable, not falsifiable because there's always some new kind of rescuing scenario that gets invented to accommodate any contradictions.

.

.

@SCVGoodToGo
How the hell did you come to that conclusion?
maybe the hand of god is talking to him?

http://1.bp.blogspot.com/_LNUZKA_lhUY/TFnCna94UaI/AAAAAAAAAS8/pQJHUHffPGk/s1600/Grog.gif


Mar 15, 2019
@SCVGoodToGo @Captain Stumpy
Where did you EVER come across ANY man-made complex system that arose by sheer chance without any human input?
You guys need to re-examine your own basic assumptions.

Here's a very good question for you to answer - where does (your) life come from? Do you REALLY think that unaided random chemical and physical processes can give rise to the biological arrangements inside even the simplest living cell? To name a few insurmountable obstacles: Chirality - left-handed only for amino acids, right-handed only for sugars, how did the proteins get into the cell membrane because you need to have a protected environment in which to first create the proteins. The code for the proteins need a protein to read it out of the DNA - which came first? How does purely material processes create the abstract logic and information required?
Life gives rise to life. God is Spirit(non-material) and hence can be everlasting -just as the bible describes. God exists 4ever.

Mar 15, 2019
Where did you EVER come across ANY man-made complex system that arose by sheer chance without any human input?
that question is not logical
if it's man-made it does not "arise by sheer chance" you idiot
where does (your) life come from?
the flying spaghetti monster - same as yours
Do you REALLY think that unaided random chemical and physical processes can give rise to the biological arrangements inside even the simplest living cell?
yes
To name a few insurmountable obstacles
no, they're not insurmountable
I would link some science, but you will ignore it as you always have
which came first?
depends on the arousal state of the chicken
God is Spirit
the FSM is pasta
I can prove mine is pasta, so can you prove yours is spirit?
just as the bible describes
erm - no
the bible is a half-to-mostly plagiarized tome of dogmatic anecdotes made up as history to justify control over idiots


Mar 15, 2019
@Stumpy:
Not observed, not verifiable

It was observed by the Creator Himself - and he then related it to Adam and so on. The bible is an internally self-consistent reference so you can use it in the seemingly circular self-referencing fashion without self-contradiction. Try that with ANY other story about our origins. God is not a man that He should lie.

You can definitely verify that kinds reproduce after their own kinds and does not morph into another over many generations. You see it for yourself, unlike the darwinian fairy tale that has NEVER been observed.

Mar 15, 2019
that question is not logical
if it's man-made it does not "arise by sheer chance" you idiot

Actually the joke is on you: You observe tremendously complex DESIGN in biological systems and you attribute that design to pure random, chance events. This is just plain foolishness. The bible has it right - "The fool said in his heart there is no God" Psalm 14:1

How else are you going to account for the complex logic inherent in said systems?

Have you EVER observed random events create complex, useful and vital systems? EVER?

Please supply a link or document that confirms your observation. If you don't have any, then maybe you should stop dead in your tracks and start to think about what you and all other atheists and non-believers are actually claiming.

Mar 15, 2019
@fred
It was observed by the Creator Himself
no, it wasn't, unless you can prove it
The bible is an internally self-consistent reference so you can use it in the seemingly circular self-referencing fashion without self-contradiction
apparently, you've never read the thing
it's full of contradictions and blatantly plagiarized mythos while misattributing half of the books
Try that with ANY other story about our origins
apparently you've never read Oglala origins
unlike the darwinian fairy tale that has NEVER been observed
you don't know much about science or DNA, apparently

so, you don't know about science and you don't know about your own tome, and you've just admitted you've never read your tome either, and yet you want to proselytize to us about it?

how is that logical?

perhaps you should be aware of your own holy comic before you dare to teach it wrongly
JER 31:27 - 31:37

Mar 15, 2019
no, they're not insurmountable
I would link some science, but you will ignore it as you always have

I don't even have to ignore them - you haven't even remotely supplied any random chemical or physical event that can construct a living cell from non-living materials all by itself with no intelligent and powerful agent being involved. Plus - you just CAN'T supply such because it doesn't exist.
Consider this - living things die and never come back to life again by themselves. Yet they have a head-start in having all the biological parts already in the right order. This is observed daily. So how much more of an uphill for non-living materials to first assemble in the right biological order BEFORE it can perform that impossible task of kick-starting the life process off in the correct sequence - all by its lonesome self?
You are on a hiding to nothing, friend. Pure, simple principles of chemistry,physics,information theory and probability are against you. Give it up.

Mar 15, 2019
@fred
You observe tremendously complex DESIGN in biological systems and you attribute that design to pure random, chance events
LOL

if your deity created the happy fun park of moistness and then decided to not only make it randomly bleed and flush out toxins which could kill the host, but then to park the funhouse next to the sewer system almost guaranteeing potential sepsis, then your deity is a complete f*cking idiot!!

and none of that even discusses the shortcomings of the male or the human form! that is just one sex of the species!
ROTFLMFAO
How else are you going to account for the complex logic inherent in said systems?
so... sugar is logical!
gotcha
Please supply a link or document that confirms your observation
bubba, I've been linking the same science to you for years

you don't understand it
you link back religious idiocy based on your delusional beliefs
then you say you're the factual one

the FSM is not amused

Mar 15, 2019
JER 31:27 - 31:37

Thanks for giving that reference. Perhaps you should pay some attention to what it says and think deeply about the implications for your own sake.

How about this one:
Ezek 18:20. "The one who sins is the one who will die. The child will not share the guilt of the parent, nor will the parent share the guilt of the child. The righteousness of the righteous will be credited to them, and the wickedness of the wicked will be charged against them." Then go on to read the whole chapter.
Or this one: Romans 3:23 "All have sinned and fall short of the glory of God"
and this one: Romans 6:23. "The wages of sin is death but the gift of God is everlasting life in Jesus Christ our Lord."
If you're going to quote things from the bible please be sure to know what it means before throwing it out in the open, displaying your shame.

Mar 15, 2019
I've been linking the same science to you for years

So why haven't you or the people creating it won the Nobel prize yet for discovering and describing the origin of life in a scientifically acceptable and coherent fashion?

I can just hope you come to your senses, friend because right now you're on the way to the eternal fire and there is no escape from there once in it. Now is the time to discover the way, the truth and the life, the path that leads to eternal joy, peace and love where there is no sorrow, no suffering, no sickness and suffering, no sin and definitely no death. The bible is there to guide you, BUT The choice is yours.

Mar 15, 2019
@fred
Perhaps you should pay some attention to what it says and think deeply about the implications for your own sake
that reference pretty much stated that you're a liar and you're presenting a false religion for the purpose of self-gain, which is directly contradictory to your own magic sky-faeries commandments

it also states that you're unaware of the "legal-ese" of the statement as you're ignorant of the historical and current implications

perhaps you should study your own tome more?
How about
funny that when presented with the words of your own tome that state you're a liar and ignoring the commandments of your own deity that you would break out the threatening "control" passages

I've been studying your religion for decades - from your own scholars

to use your own words back at you:
If you're going to quote things from the bible please be sure to know what it means before throwing it out in the open, displaying your shame.

Mar 15, 2019
@fred
because right now you're on the way to the eternal fire and there is no escape from there once in it
and yet, according to your own beliefs and tome, you can't subject me to your delusional hell because your own deity died for my sins

I don't believe in a hell outside of the one we make for ourselves in life

you know, like the one you live in driving you to post to science sites presenting delusional rantings as fact because you're such an insignificant POS that you think calling threats and advocating for torture is a good thing
Now is the time to discover the way, the truth and the life, the path that leads to eternal joy, peace and love
you mean the Flying Spaghetti Monster!

I already know the pasta-ness personally, having been chosen by said noodle-y appendage

and yea, I have been baptised in the meatball sauce of glory

Mar 15, 2019
Amazing, Freddo actually responded beyond his normal hit-and-run tactic; albeit with strawman arguments and begging the question a couple times. Really must have struck his cognitive dissonance this time. Tell me fred, do you really think you'll convert anyone to your way of "thinking" when you pour your derision on science articles?

Mar 15, 2019
freddys lack of intellect, is all the proof I need, that my Stupid Design Theory is correct,

All hail The Coyote Trickster Goddess for the defective breeding that produced freddy,
to be our perpetual class clown.

Mar 16, 2019
The bible is an internally self-consistent reference

It's extremely well known (and trivial to prove) that the bible contradicts itself. It's so well known that I don't think that Fred can claim incompetence for making this comment. This strongly suggests that Fred is a troll and a Poe. He knows that what he says is idiotic, but he doesn't really care.

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