Revealing a Non-canonical Role of Anti-apoptotic MCL-1 in Early Embryonic Development

<p>MCL-1, a well-known pro-survival BCL-2 family member, is indispensable for the survival of various cellular lineages and is also among the most frequently amplified genes in a variety of human malignancies. Gene ablation studies previously revealed that Mcl-1 deficiency leads to embryonic lethality around E3.5 during peri-implantation stage. Strikingly, the study did not detect any increase in apoptotic cells of the blastocyst, indicating a function of MCL-1 beyond regulating apoptosis. Our previous studies revealed an unrecognized role of MCL-1 in promoting mitochondrial physiology, which is independent of its classical anti-apoptotic function and requires being imported into the mitochondrial matrix. In order to understand the role of MCL-1 in early embryonic development, we used CRISPR-Cas9 to target Mcl-1’s start codon on established embryonic stem cells (ESCs). This approach resulted in the establishment of ESCs in which MCL-1’s N-terminus was truncated. Biochemical evaluation revealed that Nterminal- deleted MCL-1 retains anti-apoptotic function. However, this truncated MCL-1 is restricted to the mitochondrial outer membrane and functionally these mutated ESCs showed a dramatic defect in differentiation into the three embryonic germ layers- ectoderm, mesoderm, and ectoderm. These data suggest that in addition to MCL-1’s required antagonism of cell death by the C-terminal region, MCL-1’s N-terminus is required for efficient cellular differentiation, potentially by facilitating MCL-1’s import into the mitochondrial matrix.</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biomedical Sciences

Year dc:date.available

2017

Author dc:creator

• Yang, Xue

Contributors dc:contributor

• Joseph T. Opferman, Ph.D.

• Anti-apoptosis
• BCL-2 family
• CRISPR-Cas9
• MCL-1
• Non-canonical role
• Stem cell differentiation
• Genetic Phenomena
• Medical Cell Biology
• Medical Genetics
• Medical Sciences
• Medicine and Health Sciences
• Neoplasms

Repository record dc:identifier

https://dc.uthsc.edu/dissertations/451

OAI identifier oai:identifier

oai:dc.uthsc.edu:dissertations-1449