Gene Expression Changes During Fasting Vary Across Blubber Depth in Elephant Seals
Faculty Mentor Name
Jane Khudyakov
Research or Creativity Area
Natural Sciences
Abstract
Blubber is a thick, subcutaneous layer of adipose tissue that provides insulation, energy storage, and buoyancy in marine mammals. This layer is not uniform and shows differences in gene activity and cell composition across blubber depth. However, it is still unknown whether changes in blubber gene expression during prolonged fasting in marine mammals are uniform or differ along blubber depth. To investigate how gene activity changes across both blubber layers and fasting, blubber samples were obtained from northern elephant seals early and late in their molting fast and subdivided into 5 layers. We homogenized the samples, isolated RNA, then performed RT-qPCR targeting genes with important roles in blubber function, including the adipokine leptin (LEP), antioxidant enzyme GPX3, metabolic enzyme HMGCS2, and angiotensinogen (AGT). We normalized their values using a housekeeping gene (NONO) and compared normalized values between early and late molt and across blubber depth. From these tests, we identified that expression of HMGCS2 and AGT differed across blubber depth but did not change over fasting, whereas LEP and GPX3 expression changed over fasting in a layer-specific manner. The information from these results will allow us to gain a better understanding of genes involved in prolonged fasting in elephant seals and the role of blubber tissue in allowing marine mammals to survive long periods without food during molting or breeding.
Significance
Blubber is a thick, subcutaneous layer of adipose tissue that provides insulation, energy storage, and buoyancy in marine mammals. This layer is not uniform and shows differences in gene activity and cell composition across blubber depth. However, it is still unknown whether changes in blubber gene expression during prolonged fasting in marine mammals are uniform or differ along blubber depth. To investigate how gene activity changes across both blubber layers and fasting, blubber samples were obtained from northern elephant seals early and late in their molting fast and subdivided into 5 layers. We homogenized the samples, isolated RNA, then performed RT-qPCR targeting genes with important roles in blubber function, including the adipokine leptin (LEP), antioxidant enzyme GPX3, metabolic enzyme HMGCS2, and angiotensinogen (AGT). We normalized their values using a housekeeping gene (NONO) and compared normalized values between early and late molt and across blubber depth. From these tests, we identified that expression of HMGCS2 and AGT differed across blubber depth but did not change over fasting, whereas LEP and GPX3 expression changed over fasting in a layer-specific manner. The information from these results will allow us to gain a better understanding of genes involved in prolonged fasting in elephant seals and the role of blubber tissue in allowing marine mammals to survive long periods without food during molting or breeding
Gene Expression Changes During Fasting Vary Across Blubber Depth in Elephant Seals
Blubber is a thick, subcutaneous layer of adipose tissue that provides insulation, energy storage, and buoyancy in marine mammals. This layer is not uniform and shows differences in gene activity and cell composition across blubber depth. However, it is still unknown whether changes in blubber gene expression during prolonged fasting in marine mammals are uniform or differ along blubber depth. To investigate how gene activity changes across both blubber layers and fasting, blubber samples were obtained from northern elephant seals early and late in their molting fast and subdivided into 5 layers. We homogenized the samples, isolated RNA, then performed RT-qPCR targeting genes with important roles in blubber function, including the adipokine leptin (LEP), antioxidant enzyme GPX3, metabolic enzyme HMGCS2, and angiotensinogen (AGT). We normalized their values using a housekeeping gene (NONO) and compared normalized values between early and late molt and across blubber depth. From these tests, we identified that expression of HMGCS2 and AGT differed across blubber depth but did not change over fasting, whereas LEP and GPX3 expression changed over fasting in a layer-specific manner. The information from these results will allow us to gain a better understanding of genes involved in prolonged fasting in elephant seals and the role of blubber tissue in allowing marine mammals to survive long periods without food during molting or breeding.
