I was trying to use UCSC liftover tool to convert human coordinates to mouse. While most of the files worked, one file didnt:

chr16 86430087 86430726 Human_chr16:86430087-86430726___element_1___positive____neural_tube[12/12]__hindbrain(rhombencephalon)[12/12]___limb[3/12]_cranial_nerve[8/12] chr16 85620095 85621736 Human_chr16:85620095-85621736___element_2___negative chr16 80423343 80424652 Human_chr16:80423343-80424652___element_3___negative chr16 80372593 80373755 Human_chr16:80372593-80373755___element_4___positive____neural_tube[6/10]__hindbrain(rhombencephalon)[10/10]__midbrain(mesencephalon)[10/10]

Does anyone know why this bed file can only be converted to chr:start-end format but not bed4 format?