2020/08/31

LncRNAs transmit epigenetic information for embryonic stem cell differentiation

Thousands of different lncRNAs transmit organismal traits from parents to offspring - lncRNAs are 'poorly conserved' which means that we have nothing to do with apes


Excerpts: "Long non-coding RNA (lncRNA), a class of non-coding RNAs with more than 200 bp in length, has been shown to act as essential epigenetic regulators of stem cell pluripotency and specific lineage commitment."

"Long non-coding RNA refers to a family of non-coding RNAs with more than 200 bp in length and is transcribed by RNA polymerase II, usually 5′ capped, spliced and polyadenylated (Kung et al., 2013; Quinn and Chang, 2016). LncRNA can be transcribed from different genome regions, including introns, exons, intergenic connections, and other areas. Currently, there are about 30,000 lncRNAs identified in human and mice (Frankish et al., 2019), but only a handful part of them have been recognized for their function."

"Here, we provide an updated overview on how lncRNA epigenetically regulates PSC (pluripotent stem cell) function."
 
Mechanisms of lncRNA in regulating stem cell pluripotency. Nuclear lncRNAs regulate the expression of pluripotent genes via chromatin remodeling. While lncRNAs in cytosol mainly act as post-transcriptional regulators. They work as miRNA sponges to affect gene expression or signaling pathway.

"Previous studies have demonstrated that lncRNAs are crucial regulators for regulating stem cell pluripotency (Chen and Zhang, 2016; Rosa and Ballarino, 2016)."

"We will discuss the role of lncRNA in cell lineage commitment and focus on how lncRNA regulates PSC differentiation into adipocytes, osteogenic, muscle, cardiomyocytes, neurons, skin, and blood cells."

"The lncRNA adipogenic differentiation-induced non-coding RNA (ADINR) is induced by adipogenesis and positively regulates both PPARĪ³ and CEBPA expression by recruiting PA1 (a component of the MLL3/4 complex) to the CEBPA promoter and impacting H3K4me3 and H3K27me3 histone modification (Xiao et al., 2015)."
https://link.springer.com/article/10.1007/s00018-018-3000-z

Excerpt: "Many nuclear lncRNAs interact with histone modifiers (writers, readers, and erasers) and/or other chromatin-associated proteins, thus acting as epigenetic regulators."


"However, unlike protein-coding genes, which are largely conserved in mammals, vast majority of human lncRNAs are non-conserved, and many of them are probably lineage-specific."

Summary and conclusions:
  • lncRNAs transmit epigenetic information, especially for histones, from parents to offspring.
  • There are thousands of different lncRNAs in human sperm.
  • Most of human traits and characteristics are regulated by histone epigenetic information = histone code.
  • DNA is just passive information and it doesn't determine organismal traits.
  • It's very pseudoscientific to compare human/chimp protein coding DNA (~97% similarity) and draw evolutionary conclusions.
  • lncRNAs are poorly conserved (only 20-30% similarity) between humans and apes
The theory of evolution has major flaws. The modern synthesis has got causality in biology wrong, DNA doesn't determine organismal traits. DNA is just passive data base. Evolution never happened. Don't get lost, my friends.
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