Phenotypes associated with this allele

• Allele Symbol: Hbb-b1^tm1Shs
• Allele Name: targeted mutation 1, Takuji Shirasawa
• Allele ID: MGI:2384424
• Summary: 2 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Hbb-b1^tm1Shs/Hbb-b1^tm1Shs	involves: C57BL/6	MGI:2450607
ht2	Hbb-b1^tm1Shs/Hbb-b1^+	involves: C57BL/6CrSlc	MGI:4441584

Genotype
MGI:2450607

hm1

• Allelic Composition: Hbb-b1^tm1Shs/Hbb-b1^tm1Shs
• Genetic Background: involves: C57BL/6

• ♀: phenotype observed in females
• ♂: phenotype observed in males
• N: normal phenotype

hematopoietic system

enlarged spleen ( J:78271 )

• splenomegaly, 2.8 times heavier than wild-type controls; iron accumulation in spleen

abnormal erythropoiesis ( J:78271 )

• seen in bone marrow, showing increased erythropoiesis with the appearance of megaloblastic cells

extramedullary hematopoiesis ( J:78271 )

• marked, in the red pulp of the spleen

hemolytic anemia ( J:78271 )

hypochromic anemia ( J:78271 )

• microspheric hypochromic anemia

increased erythroid progenitor cell number ( J:78271 )

decreased erythrocyte cell number ( J:78271 )

decreased hematocrit ( J:78271 )

decreased mean corpuscular hemoglobin ( J:78271 )

decreased mean corpuscular volume ( J:78271 )

anisopoikilocytosis ( J:78271 )

increased number of Heinz bodies ( J:78271 )

• 10 days after splenectomy, erythrocytes exhibit Heinz bodies which are rarely seen in wild-type mice

reticulocytosis ( J:78271 )

• with presence of nucleated RBC precursors

increased spleen iron level ( J:78271 )

abnormal erythrocyte physiology ( J:78271 )

• mutant erythrocytes show less of an affinity on oxygen saturation than wild-type erythrocytes

• erythrocytes have a shortened lifespan

immune system

enlarged spleen ( J:78271 )

• splenomegaly, 2.8 times heavier than wild-type controls; iron accumulation in spleen

increased spleen iron level ( J:78271 )

homeostasis/metabolism

increased spleen iron level ( J:78271 )

growth/size/body

enlarged spleen ( J:78271 )

• splenomegaly, 2.8 times heavier than wild-type controls; iron accumulation in spleen

Genotype
MGI:4441584

ht2

• Allelic Composition: Hbb-b1^tm1Shs/Hbb-b1⁺
• Genetic Background: involves: C57BL/6CrSlc

hematopoietic system

anemia ( J:81902 )

• mild anemia without signs of hemolysis

abnormal hemoglobin ( J:81902 )

• the oxygen dissociation of red blood cells shows low affinity for oxygen in vitro

decreased hemoglobin content ( J:81902 )

• in peripheral blood

homeostasis/metabolism

increased carbon dioxide production ( J:81902 )

• produce more carbon dioxide in room air and hypoxic conditions

increased oxygen consumption ( J:81902 )

• consume more oxygen in room air and hypoxic conditions

• consume more oxygen in skeletal muscles by oxidative phosphorylation

hyperoxia ( J:81902 )

• enhanced tissue oxygenation

acidosis ( J:81902 )

• mutants show low arterial blood pH associated with an elevated PaCO₂ both in room air and under hypoxic conditions

increased aerobic running capacity ( J:81902 )

• run more than twice as far as wild-type mice spontaneously on a running wheel

muscle

abnormal skeletal muscle fiber type ratio ( J:81902 )

• on histochemical staining for ATPase, show a higher percentage of type IIA fibers and a lower percentage of type IIB fibers in deep regions of the muscle

• however, show no fiber hypertrophy or atrophy

respiratory system

decreased pulmonary ventilation ( J:81902 )

• mutants consistently have depressed ventilation before and during hypoxia, although they show a similiar pattern of ventilatory responses to wild-type, such as the initial hypoxic response and subsequent depression

• mutants do not show lung disease causing hypoventilation

cellular

abnormal aerobic respiration ( J:81902 )

• succinate dehydrogenase activities in both type IIA and type IIB muscle fibers are greater in deep regions of the tibialis anterior compared to wild-type mice